Pressure sensor, sensor array, method for manufacturing sensor array, and grasping apparatus

ABSTRACT

A pressure sensor includes: a supporting body which has an opening; a pressure detecting portion which includes a supporting film provided on the supporting body and having a diaphragm portion closing the opening, and a piezoelectric body provided on the diaphragm portion and deflecting to output an electric signal; a frame body which has, on the pressure detecting portion, a cylindrical cavity along a film thickness direction of the supporting film, and is formed, in plan view when viewed from the film thickness direction of the supporting film, at a position where a cylindrical inner peripheral wall of the cavity overlaps with the opening, or outside of the opening; a sealing film which closes the frame body; and a silicone oil which is filled in an inner space formed of the cylindrical inner peripheral wall of the cavity, the sealing film, and the pressure detecting portion.

BACKGROUND

1. Technical Field

The present invention relates to a pressure sensor, a sensor array, amethod for manufacturing a sensor array, and a grasping apparatus.

2. Related Art

Diaphragm-type ultrasonic sensor devices have been known in the relatedart (for example, refer to JP-A-2006-319945).

This type of ultrasonic sensor device includes a semiconductor substratehaving an opening, two layers of electrodes on an insulating film formedon the surface of the semiconductor substrate to close the opening, anda PZT ceramic thin film layer (piezoelectric film) interposed betweenthe two layers of electrodes. Then, a membrane which has a diaphragmwith a multilayer film structure stacked in a planar manner with respectto the opening and a piezoelectric body configured of the piezoelectricfilm and the two layers of electrodes is formed. In the ultrasonicsensor device, when a predetermined voltage is applied from the upperand lower electrodes to the PZT ceramic thin film layer, the PZT ceramicthin film layer expands and contracts in its in-plane direction, andaccordingly, the diaphragm deflects and vibrates in a directionperpendicular to the plane direction to output ultrasonic waves.

In JP-A-2006-319945, a portion of the PZT ceramic thin film layer isexposed to the outside.

It has been generally known that such an ultrasonic sensor device can beapplied to a pressure sensor.

For example, in the case where the pressure sensor is applied to agrasping apparatus which grasps an object, the pressure sensor detects,based on a deflection state of the piezoelectric body of the membrane,pressure when the object is grasped by arms or the like of the graspingapparatus.

In this case, since the object directly contacts the piezoelectric filmexposed to the outside, a force is locally applied to the piezoelectricbody or diaphragm of the membrane, causing a problem that thepiezoelectric body or diaphragm of the membrane is likely to be broken.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the problem described above, and the invention can be realizedas the following modes or application examples.

First Application Example

A first application example is directed to a pressure sensor including:a supporting body which has an opening; a pressure detecting portionwhich includes a supporting film provided on the supporting body andhaving a diaphragm portion closing the opening, and a piezoelectric bodyprovided on the diaphragm portion and deflecting to output an electricsignal; a frame body which has, on the pressure detecting portion, acylindrical cavity along a film thickness direction of the supportingfilm, and is formed, in plan view when viewed from the film thicknessdirection of the supporting film, at a position where a cylindricalinner peripheral wall of the cavity overlaps with an inner peripheraledge of the opening, or outside of the inner peripheral edge of theopening; a sealing film which closes the frame body; and a pressuremedium which is filled in an inner space formed of the cylindrical innerperipheral wall of the cavity, the sealing film, and the pressuredetecting portion.

According to this configuration, a portion of the supporting film wherethe opening is closed serves as the diaphragm portion which detectspressure, and the diaphragm portion and the piezoelectric body stackedon the diaphragm portion form a membrane. That is, in the cavity of theframe body formed on the pressure detecting portion, a portion(membrane) of the pressure detecting portion is contained.

The piezoelectric body of the pressure detecting portion is contained inthe frame body, and a pressure medium which disperses a force is filledin the inner space of the frame body. The frame body is sealed by thesealing film.

Therefore, when the pressure sensor is applied to a grasping apparatuswhich grasps an object, the pressure generated between the sealing filmand the object is transmitted to the piezoelectric body via the pressuremedium. That is, the object does not directly contact the piezoelectricbody, and a force when the object contacts the sealing film istransmitted to the pressure detecting portion via the pressure medium.Thus, the dispersed force is applied to the diaphragm portion of thepressure detecting portion which detects pressure. Accordingly, thelocal application of force to the diaphragm portion can be prevented,the breakage of the pressure detecting portion can be prevented, andfurther, the breakage of the membrane can be prevented. The term “on” asused herein means that a specific member is positioned in a directionfrom the supporting body toward the supporting film, which also includessuch a case that specific members are not in contact with each other.

Second Application Example

A second application example is directed to the pressure sensoraccording to the application example, wherein the frame body hasflexibility.

According to the application example, since the frame body hasflexibility, the frame body contracts when a force is applied to theframe body. Therefore, since the force is transmitted to the diaphragmportion via the pressure medium filled in the inner space of the framebody, pressure can be favorably detected.

Third Application Example

A third application example is directed to a sensor array including aplurality of the pressure sensors according to the application examplearranged therein, wherein a gap is formed between frame bodies of thepressure sensors next to each other.

According to the application example, a gap is formed between the framebodies of the pressure sensors. As the gap, for example, a width is setsuch that the frame bodies contact each other at a value less than adeformation limit of the pressure sensor. When the pressure sensordeforms with pressure, and before the pressure sensor deforms at a valueequal to or greater than the deformation limit, the pressure sensorcontacts the frame body of the next pressure sensor. Then, since theframe bodies of the pressure sensors function as each other'sreinforcing materials, the reliability (resistance to pressure) of thesensor array can be enhanced.

Fourth Application Example

A fourth application example is directed to a sensor array, including:the pressure sensor described above; and an ultrasonic sensor which hasa second supporting body having a second opening, and an ultrasonictransducer portion including a second supporting film which is providedon the second supporting body and has a second diaphragm portion closingthe second opening, and a second piezoelectric body which is provided onthe second diaphragm portion and deflects by the application of voltage.

According to the application example, the sensor array includes twokinds of sensors, the pressure sensor and the ultrasonic sensor.Therefore, by applying the sensor array according to the applicationexample of the invention to arms or the like of a grasping apparatuswhich grasps an object for example, the object can be recognized by theultrasonic sensor, and pressure in a state where the object is graspedby the arms or the like can be detected by the pressure sensor.

The frame body of the ultrasonic sensor can be formed in the same stepas that of the frame body constituting the pressure sensor. Since it isonly necessary for the ultrasonic sensor to be configured of constituentmembers excepting a pressure medium and a sealing film, the ultrasonicsensor can be easily manufactured. That is, the ultrasonic sensor can bemanufactured in the course of manufacturing the pressure sensor.Accordingly, manufacturing steps of the sensor array can be simplified,which can reduce the manufacturing cost.

Fifth Application Example

A fifth application example is directed to the sensor array according tothe application example, wherein the ultrasonic sensor further includesa second frame body which has, on the ultrasonic transducer portion, acylindrical second cavity along a film thickness direction of the secondsupporting film, and is formed, in plan view when viewed from the filmthickness direction of the second supporting film, at a position where acylindrical inner peripheral wall of the second cavity overlaps with aninner peripheral edge of the second opening, or outside of the innerperipheral edge of the second opening.

According to the application example, in the sensor array, theultrasonic sensor includes the second frame body. Therefore, when thesensor array is applied to arms or the like of a grasping apparatuswhich grasps an object for example, the deterioration or breakage of theultrasonic sensor due to contact with the object can be prevented.

Sixth Application Example

A sixth application example is directed to the sensor array according tothe application example, wherein the sensor array includes a pluralityof the pressure sensors and a plurality of the ultrasonic sensors, and agap is formed between frame bodies of the pressure sensors next to eachother, between second frame bodies of the ultrasonic sensors next toeach other, or between a frame body of the pressure sensor and a secondframe body of the ultrasonic sensor next to each other.

According to the application example, the ultrasonic sensor and thepressure sensor are next to each other via a gap. Therefore, thetransmission of vibrations of the second diaphragm portion of theultrasonic sensor is suppressed by the gap portion. Therefore, since thevibrations from the ultrasonic sensor reach the pressure sensor in anattenuated state, it is possible to provide a sensor array which candetect pressure with good accuracy.

Seventh Application Example

A seventh application example is directed to the sensor array accordingto the application example, wherein the supporting body and the secondsupporting body are a common supporting body which is common to them,and a height from the common supporting body to a top of the pressuresensor is higher than a height from the common supporting body to a topof the ultrasonic sensor.

According to the application example, the top of the pressure sensorserves as an abutment surface. That is, since the top of the pressuresensor abuts on an object prior to the top of the ultrasonic sensor, thetop of the ultrasonic sensor does not contact the object in this state.Therefore, the ultrasonic sensor can escape deterioration due topressure and can maintain high reliability (resistance to pressure).

Eighth Application Example

An eighth application example is directed to the sensor array accordingto the application example, wherein the pressure sensors and theultrasonic sensors have a two-dimensional array structure in which thepressure sensor and the ultrasonic sensor are alternately arranged.

According to the application example, since the pressure sensors and theultrasonic sensors have a two-dimensional array structure in which thepressure sensor and the ultrasonic sensor are alternately arranged, aposition at which the ultrasonic sensor recognizes an object and aposition at which the pressure sensor detects a force grasping theobject are substantially the same position of the object. Therefore,position control by the ultrasonic sensor and pressure control by thepressure sensor can be smoothly switched from one to the other.

Ninth Application Example

A ninth application example is directed to the sensor array according tothe application example, wherein a dimension of the gap is set such thatwhen a first pressure is applied to the pressure sensor, the frame bodydeforms to contact the frame body of the next pressure sensor or contactthe second frame body of the next ultrasonic sensor, and the firstpressure is smaller than an allowable pressure of the pressure sensor.

According to the application example, a gap is formed between thepressure sensors next to each other, between the ultrasonic sensors nextto each other, or between the pressure sensor and the ultrasonic sensornext to each other. In this case, the dimension of the gap is set suchthat when the frame body of the pressure sensor is deformed by a firstpressure, the frame body contacts the frame body of the next pressuresensor or the second frame body of the next ultrasonic sensor in a stateless than the allowable pressure of the pressure sensor. Then, since theframe body contacts the frame body of the pressure sensor or the secondframe body of the ultrasonic sensor with the first pressure in the rangeof the allowable pressure of the pressure sensor, the frame bodiesfunction as each other's reinforcing materials. Therefore, thereliability (resistance to pressure) of the sensor array can beenhanced. The term. “allowable pressure” as used herein means a maximumpressure by which the diaphragm portion or the second diaphragm portionof the pressure sensor or the ultrasonic sensor is not broken.

Tenth Application Example

A tenth application example is directed to a method for manufacturing asensor array including a plurality of pressure sensors, including:forming a supporting film on a supporting body and forming apiezoelectric body on the supporting film to thereby form a plurality ofpressure detecting portions; forming, on the plurality of pressuredetecting portions, a frame body layer which covers the piezoelectricbody; removing portions of the frame body layer formed in the forming ofthe frame body layer to thereby form frame bodies each of which includesa cavity having a cylindrical inner peripheral wall so as to have a gapbetween frame bodies next to each other; filling a pressure medium inthe cavity; and forming, by a roll coating method, a sealing film whichcloses the cavity to seal the pressure medium.

According to this configuration, a sensor array including a plurality ofpressure sensors defined with a gap can be manufactured. A dimension ofthe gap is set such that when the frame body of the pressure sensor isdeformed, the frame body contacts the frame body of the next pressuresensor in a state less than an allowable pressure of the pressuresensor, whereby it is possible to form frame bodies which use the framebodies of the pressure sensors as each other's reinforcing materials ina range of the allowable pressure of the pressure sensor. By providingthe gap, it is possible to provide a method for manufacturing a sensorarray in which interference from the next pressure sensor can besuppressed.

Eleventh Application Example

An eleventh application example is directed to the method formanufacturing the sensor array according to the application example,further including forming a groove which divides the supporting film ata position overlapping with the gap in plan view when the supportingfilm is viewed from a film thickness direction thereof.

According to the application example, it is possible to avoidinterference between the pressure sensors. Since the pressure sensorsare connected to each other via the groove, and therefore, interferenceis suppressed, it is possible to provide a method for manufacturing asensor array which can detect pressure with high accuracy.

Twelfth Application Example

A twelfth application example is directed to the method formanufacturing the sensor array according to the application example,further including: bonding a sensor substrate to the lower side of thesupporting body; and forming, while leaving at least a portion of thesensor substrate, a groove which divides the supporting body in the gap.

According to the application example, it is possible to provide a methodfor manufacturing a sensor array which avoids interference between thepressure sensors. Since a groove formed by removing the supporting bodyis formed between the pressure sensors, the pressure sensors do notinterfere with each other, making it possible to provide a method formanufacturing a sensor array which can detect pressure with highaccuracy. The term “lower side” as used herein means a directionopposite to the direction indicated by the “on” described above.

Thirteenth Application Example

A thirteenth application example is directed to the method formanufacturing the sensor array according to the application example,further including: dividing, after the forming of the sealing film, thesensor array into blocks each of which includes one or more the pressuresensors; and bonding the block to a sensor substrate such that the lowerside of the pressure sensor is positioned on the sensor substrate side.

According to the application example, since the pressure sensors areonce divided and then bonded to the sensor substrate, the applicationexample can deal with a sensor substrate larger than a supporting body.

Fourteenth Application Example

A fourteenth application example is directed to a method formanufacturing a sensor array including a plurality of pressure sensorsand a plurality of ultrasonic sensors, including: forming a supportingfilm on a supporting body and forming a piezoelectric body on thesupporting film to thereby form a plurality of pressure detectingportions and a plurality of ultrasonic transducer portions; forming, onthe plurality of pressure detecting portions and the plurality ofultrasonic transducer portions, a frame body layer which covers thepiezoelectric body; removing portions of the frame body layer formed inthe forming of the frame body layer to thereby form a plurality of framebodies which are defined by a gap and each of which includes a cavityhaving a cylindrical inner peripheral wall; filling a pressure medium insome of the cavities; and forming, by a roll coating method, a sealingfilm which closes the cavity to seal the pressure medium.

According to this configuration, a sensor array including a plurality ofpressure sensors and a plurality of ultrasonic sensors which are definedwith a gap can be manufactured. A dimension of the gap is set such thatwhen the frame body of the pressure sensor is deformed, the frame bodycontacts the next pressure sensor or the second frame body of the nextultrasonic sensor in a state less than an allowable pressure of thepressure sensor, whereby it is possible to provide a method formanufacturing frame bodies which use the frame body of the pressuresensor or the second frame body of the ultrasonic sensor as each other'sreinforcing materials in the range of the allowable pressure of thepressure sensor. Moreover, by providing the gap, it is possible toprovide a method for manufacturing a sensor array in which interferencefrom the next pressure sensor or ultrasonic sensor can be suppressed.

Fifteenth Application Example

A fifteenth application example is directed to the method formanufacturing the sensor array according to the application example,further including forming a groove which divides the supporting film ata position overlapping with the gap in plan view when the supportingfilm is viewed from a film thickness direction thereof.

According to the application example, the ultrasonic sensor and thepressure sensor are formed so as to be next to each other via a grooveformed by removing the supporting film. Therefore, the vibrations of thesecond diaphragm portion of the ultrasonic sensor are absorbed by thegroove portion. That is, since the vibrations from the ultrasonic sensorreach the pressure sensor in an attenuated state, it is possible toprovide a method for manufacturing a sensor array including a pressuresensor which can detect pressure with good accuracy.

Sixteenth Application Example

A sixteenth application example is directed to the method formanufacturing the sensor array according to the application example,further including: bonding a sensor substrate to the lower side of thesupporting body; and forming, while leaving at least a portion of thesensor substrate, a groove which divides the supporting body at aposition overlapping with the gap in plan view when the supporting filmis viewed from a film thickness direction thereof.

According to the application example, it is possible to provide amanufacturing method by which interference between the pressure sensorsor the ultrasonic sensors can be avoided. Since the pressure sensors orthe ultrasonic sensors are formed by mechanically dividing themincluding the supporting body, they do not interfere with each other,making it possible to provide a method for manufacturing a sensor arraywhich can detect pressure with high accuracy.

Seventeenth Application Example

A seventeenth application example is directed to the method formanufacturing the sensor array according to the application example,further including: dividing, after the forming of the sealing film, thesensor array into blocks each of which includes one or more the pressuresensors or the ultrasonic sensors; and bonding the block to a sensorsubstrate such that the lower side of the pressure sensor is positionedon the sensor substrate side.

According to the application example, since the ultrasonic sensors orthe pressure sensors are once divided and then bonded to the sensorsubstrate, the application example can deal with a sensor substratelarger than a supporting body.

Eighteenth Application Example

An eighteenth application example is directed to a grasping apparatusincluding the sensor array described above and grasping an object,including: a pair of grasping arms which grasp the object and each ofwhich is provided with at least one the sensor array on a contactsurface with which the object contacts; a grasp detecting unit whichdetects a grasping state of the object based on an electric signaloutput from the sensor array; and a drive control unit which controlsthe driving of the grasping arms based on the grasping state.

According to this configuration, when an object is away from thegrasping arms, the driving speed of the grasping arms is increased foroperation, whereby the time until the grasping arms approach the objectcan be shortened. When the object is close to the grasping arms, thedriving speed of the grasping arms is reduced, whereby a collisionbetween the grasping arms and the object can be avoided. After thecontact of the object with the grasping arms, grasping pressure can beadjusted using a signal from the pressure sensor. That is, it ispossible to provide a grasping apparatus which can grasp an object withprecise grasping pressure in a short time.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic view of a grasping apparatus.

FIG. 2 is a perspective view showing a sensor array.

FIGS. 3A and 3B are cross-sectional views showing an ultrasonic sensorand a pressure sensor, respectively.

FIGS. 4A to 4C show manufacturing steps of the sensor array.

FIGS. 5A to 5C show manufacturing steps of the sensor array.

FIGS. 6A to 6C show manufacturing steps of the sensor array.

FIGS. 7A and 7B show manufacturing steps of the sensor array.

FIG. 8 shows a modified example according to a first embodiment.

FIG. 9 is a perspective view showing a sensor array.

FIGS. 10A, 10B, and 10C are a plan view and cross-sectional views,respectively, showing the sensor array.

FIGS. 11A to 11H are step cross-sectional views for explainingmanufacturing steps of the sensor array.

FIGS. 12A to 12D are step cross-sectional views for explainingmanufacturing steps of the sensor array.

FIG. 13 is a perspective view showing a sensor array.

FIGS. 14A and 14B are a plan view and a cross-sectional view,respectively, showing the sensor array.

FIGS. 15A and 15B are cross-sectional views when pressure is applied tothe sensor array.

FIGS. 16A to 16G are step cross-sectional views for explainingmanufacturing steps of the sensor array.

FIGS. 17A to 17D are step cross-sectional views for explainingmanufacturing steps of the sensor array.

FIG. 18 is a perspective view showing a sensor array.

FIGS. 19A, 19B, and 19C are a plan view and cross-sectional views,respectively, showing the sensor array.

FIG. 20 is a perspective view showing a sensor array.

FIGS. 21A and 21B are a plan view and a cross-sectional view,respectively, showing the sensor array.

FIG. 22 is a block diagram for explaining a grasping operation of thegrasping apparatus.

FIG. 23 is a flowchart for explaining the grasping operation of thegrasping apparatus.

FIGS. 24A to 24C are timing diagrams for explaining the graspingoperation of the grasping apparatus.

FIG. 25 is a cross-sectional view showing a sensor array.

FIG. 26 shows a manufacturing step of the sensor array.

FIGS. 27A to 27C show manufacturing steps of the sensor array.

FIG. 28 is a cross-sectional view showing the sensor array.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments according to the invention will be describedbased on the drawings.

First Embodiment Schematic Configuration of Grasping Apparatus

FIG. 1 is a schematic view of a grasping apparatus 1.

The grasping apparatus 1 is an apparatus which grasps, for example, anobject 10. The grasping apparatus 1 recognizes the position of theobject 10 to grasp the object. The grasping apparatus 1 includes asupporting member 2 and a pair of arms 3 as grasping arms which extendfrom the supporting member 2.

The supporting member 2 is formed in a longitudinal rod shape andincludes a drive mechanism which moves the pair of arms 3 toward and/oraway from each other.

The arms 3 are portions which grasp the object 10 and operate indirections toward and/or away from each other. At a portion of the arm 3with which the object 10 contacts, a substantially rectangular graspingsurface 31, for example, is formed. A sensor array 4 (refer to FIG. 2)is attached to the grasping surface 31.

Configuration of Sensor Array

FIG. 2 is a perspective view showing a sensor array including ultrasonicsensors and pressure sensors. FIG. 7B is a step cross-sectional viewshowing a manufacturing step of the sensor array and is also across-sectional view showing the structure of the sensor array shown, inFIG. 2, which includes a common supporting body 51, 61 supporting theultrasonic sensors 5 and the pressure sensors 6.

The sensor array 4 shown in FIG. 7B has the common supporting body 51,61 in which the supporting body 61 provided with the pressure sensor andthe second supporting body 51 provided with the ultrasonic sensor areused in common. The sensor array 4 includes the plurality of ultrasonicsensors 5 and the plurality of pressure sensors 6 which are mounted onthe common supporting body 51, 61. Moreover, in the sensor array 4, theultrasonic sensors 5 and the pressure sensors 6 have a two-dimensionalarray structure in which the ultrasonic sensor 5 and the pressure sensor6 are alternately arranged along, for example, a predetermined firstdirection (X-direction) and a second direction (Y-direction)perpendicular to the first direction (X-direction).

The ultrasonic sensor 5 and the pressure sensor 6 are provided on thecommon supporting body 51, 61 which is provided in common to theultrasonic sensor 5 and the pressure sensor 6, and are electricallyconducted to a not-shown control portion via an electrode pattern whichis formed on the common supporting body 51, 61. A gap is providedbetween second frame bodies 54, between frame bodies 64, and between thesecond frame body 54 and the frame body 64.

In the following description, the common supporting body 51, 61 will bedescribed while being appropriately separated into the supporting body61 and the second supporting body 51.

The term “on” as used herein means that a specific member is positionedin a direction from the common supporting body 51, 61 toward the framebody 64 and the second frame body 54, which also includes such a casethat specific members are not in contact with each other.

Configuration of Ultrasonic Sensor

FIG. 3A is a cross-sectional view showing the configuration of theultrasonic sensor 5.

The ultrasonic sensor 5 transmits ultrasonic waves to the object 10 andreceives reflected waves, thereby detecting the presence or absence ofthe object 10, or the distance to the object 10. The ultrasonic sensor 5includes a second supporting film 52, a second piezoelectric body 53,the second frame body 54, and a protective film 55 which are stacked inorder on the second supporting body 51.

The second supporting film 52 and the second piezoelectric body 53constitute an ultrasonic transducer portion 11.

The second supporting body 51 is formed of a single-crystal siliconsubstrate and formed to a thickness of about 200 μm. Moreover, in thesecond supporting body 51, a circular second opening 51A, in plan viewwhen the second supporting film 52 is viewed from its film thicknessdirection, is formed by dry etching.

The second supporting film 52 closes the second opening 51A of thesecond supporting body 51, is configured of a first oxide film 52A and asecond oxide film 52B which are stacked on the surface of the secondsupporting body 51, and is formed of the two layers. A portion of thesecond supporting film 52 where the second opening 51A is closed servesas a second diaphragm portion 57. The second diaphragm portion 57 andthe second piezoelectric body 53 which is provided on the seconddiaphragm portion 57 and deflects by the application of voltageconstitute a membrane 8.

The first oxide film 52A is formed of, for example, SiO₂ and formed to athickness of about 1 μm by thermally oxidizing the surface of thesingle-crystal silicon substrate of the second supporting body 51. Thefirst oxide film 52A may be formed by, other than the thermal oxidationof the surface, a chemical vapor deposition (CVD) method usingtetraethoxysilane (TEOS), sputtering, vapor deposition, coating, or thelike.

The second oxide film 52B is formed of, for example, ZrO₂ and formed onthe first oxide film 52A so as to finally have a thickness of about 3 μmby depositing Zr by sputtering and thermally oxidizing the same. Thesecond oxide film 52B is a layer for preventing the peeling of alater-described second piezoelectric film 531 of the secondpiezoelectric body 53 when the second piezoelectric film 531 is formedby baking. That is, when the second piezoelectric film 531 (for example,lead zirconate titanate (PZT)) is baked, in the case where the secondoxide film 52B is not formed, Pb is diffused in the first oxide film52A. Therefore, the melting point of the second oxide film 52B islowered, and air bubbles are generated on the surface of the first oxidefilm 52A, whereby the second piezoelectric film 531 is peeled due to theair bubbles. Moreover, when the second oxide film 52B is not present,there also arises a problem that the deflection efficiency to the strainof the second piezoelectric film 531 is reduced. On the other hand, byforming the second oxide film 52B on the first oxide film 52A,inconveniences such as the peeling of the second piezoelectric film 531or the decrease in deflection efficiency can be avoided. The secondoxide film 52B may be formed by a CVD method, vapor deposition, coating,or the like other than a sputtering method.

In this case, a diameter dimension D′ of the second opening 51A isappropriately set in a range from, for example, about one hundred μm toseveral hundreds μm according to the natural frequency of the seconddiaphragm portion 57. The second diaphragm portion 57 vibrates, so thatultrasonic waves are transmitted toward the object 10 (refer to FIG. 1)side.

The second piezoelectric body 53 is a film-like member which is formedconcentrically with the second opening 51A in plan view of the sensor.The diameter dimension of the second piezoelectric body 53 is smallerthan the diameter dimension D′ of the second opening 51A. The secondpiezoelectric body 53 includes the second piezoelectric film 531 andelectrodes (a lower electrode 532 and an upper electrode 533) whichapply voltage to the second piezoelectric film 531. The term “diameterdimension of piezoelectric body” as used herein means the diameter of aregion where the lower electrode, the piezoelectric film, and the upperelectrode are stacked.

The piezoelectric film 531 is formed of, for example, PZT made into afilm. Although, in the embodiment, PZT is used as the piezoelectric film531, any material may be used as long as the material can contract andexpand in an in-plane direction by the application of voltage. Forexample, lead titanate (PbTiO₃), lead zirconate (PbZrO₃), lead lanthanumtitanate ((Pb, La) TiO₃), or the like may be used.

The lower electrode 532 and the upper electrode 533 are electrodes whichare formed with the piezoelectric film 531 interposed therebetween.

The lower electrode 532 is formed below the second piezoelectric film531. The upper electrode 533 is formed on the second piezoelectric film531.

The upper electrode 533 and the lower electrode 532 are drawn through anot-shown drawing portion which is formed on the back side (the secondopening 51A side) of the second diaphragm portion 57, are connected tothe not-shown control portion of the sensor array 4, and apply apredetermined voltage to the piezoelectric film 531 based on a voltagesignal input from the control portion.

The second frame body 54 is cylindrically formed of a permanent resistmade of a synthetic resin material having flexibility and formed to athickness of about 100 μm to 600 μm. Moreover, with a cylindrical innerperipheral wall 541 provided in the second frame body 54, a cavity 54Aalong the film thickness direction of the second supporting film 52 isformed. The second frame body 54 is formed such that in plan view whenviewed from the film thickness direction of the second supporting film52, a cylindrical inner peripheral edge of the cavity 54A which iscylindrical is positioned to be overlapped with an inner peripheral edgeof the second opening 51A or positioned outside of the inner peripheraledge. In this case, the inner diameter dimension of the second framebody 54 is formed so as to have substantially the same dimension as thatof the second opening 51A (in the case of overlapping). In the cavity54A of the second frame body 54, the membrane 8 is contained. Forexample, the second frame body 54 can be formed using permanent resistTMMR™ S2000 of TOKYO OHKA KOGYO CO., LTD.

As the material for forming the second frame body 54, a photosensitiveresin film such as of a dry film resist may be used other than apermanent resist.

The protective film 55 is a portion which contacts the object 10, isformed of a dry film resist made of a synthetic resin material havingflexibility, similarly to the second frame body 54, and is formed to athickness of about 100 μm. Moreover, the protective film 55 is formed ina ring shape to cover an upper end surface of the second frame body 54.For example, the protective film 55 can be formed using dry film resistTMMF™ S2000 of TOKYO OHKA KOGYO CO., LTD.

Operation of Ultrasonic Sensor

In the ultrasonic sensor 5 described above, when a drive voltage havinga predetermined cycle is applied from the control portion between thelower electrode 532 and the upper electrode 533 of the secondpiezoelectric body 53, the piezoelectric film 531 expands or contractsin its plane direction.

When the piezoelectric film 531 contracts in the plane direction, thesecond piezoelectric body 53 side of the second diaphragm portion 57 iscontracted in the plane direction, so that the second diaphragm portion57 convexly deflects toward the second supporting body 51 side. When thepiezoelectric film 531 expands in the plane direction, the secondpiezoelectric body 53 side of the second diaphragm portion 57 isexpanded in the plane direction, so that the second diaphragm portion 57convexly deflects toward the second piezoelectric body 53 side.

Thus, the second diaphragm portion 57 vibrates in a directionperpendicular to the plane direction of the second supporting film 52,and ultrasonic waves at a frequency according to the predetermined drivevoltage cycle is transmitted from the second diaphragm portion 57. Thatis, the second diaphragm portion 57 functions as a transmitting portionwhich transmits ultrasonic waves toward the object 10 (refer to FIG. 1).Further, the second diaphragm portion 57 also functions as a receivingportion which receives ultrasonic waves reflected by the object 10. Thatis, in the control portion of the sensor array 4, the position of theobject 10 can be detected based on the time from the transmission ofultrasonic waves to the reception of ultrasonic waves reflected by theobject 10 and the intensity of vibrations.

Configuration of Pressure Sensor

FIG. 3B is a cross-sectional view showing the pressure sensor 6.

The pressure sensor 6 detects pressure when, for example, the graspingsurfaces 31 of the arms 3 of the grasping apparatus 1 (refer to FIG. 1)grasp the object 10. The pressure sensor 6 provided on the graspingsurface 31 includes a supporting film 62, a piezoelectric body 63 (apiezoelectric film 631, a lower electrode 632, and an upper electrode633), the frame body 64, and a sealing film 65 which are stacked inorder on the supporting body 61.

In this case, the supporting body 61 is a common supporting body whichis common with the second supporting body 51 of the ultrasonic sensor 5,and the configurations of the supporting film 62, the piezoelectric body63, and the frame body 64 are similar to those of the second supportingfilm 52, the second piezoelectric body 53, and the second frame body 54of the ultrasonic sensor 5, respectively. Therefore, the description isomitted.

The supporting film 62 and the piezoelectric body 63 constitute apressure detecting portion 9.

The frame body 64 is formed cylindrically, similarly to the second framebody 54 of the ultrasonic sensor 5, and has a cavity 64A. In the cavity64A, the membrane 8 including a diaphragm portion 67 which is a portionof the supporting film 62 where an opening 61A is closed and thepiezoelectric body 63 provided on the diaphragm portion 67 is contained.

A silicone oil 20 as a pressure medium is filled in an inner space 66formed of a cylindrical inner peripheral wall 641 of the cavity 64A, thesealing film 65, and the pressure detecting portion 9.

The sealing film 65 closes the inner space 66 to seal the silicone oil20. As the material to be filled in the inner space 66, any materialwhich disperses pressure may be used. Other than the silicone oil 20,for example, a silicone rubber, a polymer gel, a synthetic gel, anatural gel, a polymer resin, or the like may be used. The frame body 64is formed such that in plan view when viewed from the film thicknessdirection of the supporting film 62, a cylindrical inner peripheral edgeof the cavity 64A which is cylindrical is positioned to be overlappedwith an inner peripheral edge of the opening 61A or positioned outsideof the inner peripheral edge. In this case, the inner diameter dimensionof the frame body 64 is formed so as to have substantially the samedimension as a diameter dimension D of the opening 61A (in the case ofoverlapping).

The sealing film 65 is a portion which contacts the object 10 (refer toFIG. 1), similarly to the protective film 55, and is formed in acircular shape so as to close the inner space 66 to seal the siliconeoil 20. Moreover, the sealing film 65 is a portion which seals thesilicone oil 20 and contacts the object 10. The sealing film 65 isformed of a material similar to that of the protective film 55. Forexample, the sealing film 65 can be formed using dry film resist TMMF™S2000 of TOKYO OHKA KOGYO CO., LTD.

As the material for forming the sealing film 65, a photosensitive resinfilm such as of a permanent resist may be used other than a dry filmresist.

Since the silicone oil 20 is filled in the inner space 66, an impactwhen the object 10 contacts the sealing film 65 is dispersed over theentire membrane 8.

When a pressure medium filled in the inner space 66 is a material whichdoes not leak, such as a polymer gel, the sealing film 65 may not beprovided.

Operation of Pressure Sensor

In the pressure sensor 6 described above, when the object 10 is graspedby the arms 3 as shown in FIG. 1, the object 10 abuts on the sealingfilm 65 shown in FIG. 3B, and the frame body 64 contracts in thethickness direction. In this case, the silicone oil 20 filled in theinner space 66 of the frame body 64 disperses a force when the object 10abuts on the sealing film 65 over the entire membrane 8, and the forceis transmitted to the diaphragm portion 67. The diaphragm portion 67deflects with the transmitted force, and voltage according to thedeflection amount is generated in the piezoelectric film 631. Thus, anelectric signal according to the generated voltage is output from theupper electrode 633 and the lower electrode 632, whereby pressure isdetected.

Method for Manufacturing Sensor Array

Next, a method for manufacturing a sensor array will be described.

FIGS. 4A to 7B are step cross-sectional views showing manufacturingsteps of a sensor array having the structure. In FIGS. 4A to 7B,manufacturing steps of the ultrasonic sensor 5 are shown on the leftwhile manufacturing steps of the pressure sensor 6 are shown on theright.

In the following description, a pair of ultrasonic sensor 5 and pressuresensor 6 are described. However, this is applicable also to the case ofa plurality of ultrasonic sensors 5 and a plurality of pressure sensors6 (refer to FIG. 2).

First, a single-crystal silicon substrate which serves as the commonsupporting body 51, 61 (a thickness of about 650 μm) where the opening61A and the second opening 51A are not formed is prepared, and thesurface of the substrate is thermally oxidized, whereby the first oxidefilm 52A, 62A formed of SiO₂ is formed so as to have a thickness ofabout 1 μm. Using ZrO₂ formed by depositing Zr by sputtering andthermally oxidizing the same, the second oxide film 52B, 62B is formedon the first oxide film 52A, 62A so as to have a thickness of about 3μm. FIG. 4A shows the cross-sectional view in a state where the step sofar is completed.

Next, in an argon gas atmosphere under a predetermined pressure, asubstance for lower electrode is deposited by sputtering on the secondoxide film 52B, 62B. A not-shown photoresist is coated on a surfacewhere the common supporting film 52, 62 is formed so as to be stacked onthe common supporting body 51, 61, and exposed and developed by aphotolithography method. Further by an etching process, the lowerelectrodes 532 and 632 are patterned. In this case, any value can betaken for a gap between the lower electrodes 532 and 632 as long as theelectrodes are not in contact with each other. FIG. 4B shows thecross-sectional view in a state where the steps so far are completed.

Next, a substance for the piezoelectric films 531 and 631 is depositedby sputtering on the lower electrodes 532 and 632. By patterning by aphotolithography method and an etching process, the piezoelectric films531 and 631 are formed. FIG. 4C shows the cross-sectional view in astate where the steps so far are completed.

Next, a substance for the upper electrodes 533 and 633 is deposited bysputtering so as to cover the lower electrodes 532 and 632 and thesecond oxide film 52B, 62B. By patterning by a photolithography methodand an etching process, the upper electrodes 533 and 633 are formed.Thus, the ultrasonic transducer portion 11 and the pressure detectingportion 9 are formed on the ultrasonic sensor 5 side and the pressuresensor 6 side, respectively (piezoelectric body sensor portion formingstep). FIG. 5A shows the cross-sectional view in a state where the stepsso far are completed.

Next, the common supporting body 51, 61 is grinded so that the thicknessis reduced to about 200 μm. This is because when the common supportingbody 51, 61 which has been grinded to a desired thickness dimension isprepared in the first step, the common supporting body 51, 61 may bewarped during the manufacturing steps. FIG. 5B shows the cross-sectionalview in a state where the steps so far are completed.

Next, a permanent resist is coated as a frame body layer 70 on the upperelectrodes 533 and 633 using a spin coating apparatus or a squeegee.Thus, the frame body layer 70 is formed so as to cover the piezoelectricbody 63 and the second piezoelectric body 53 (frame body layer formingstep). FIG. 5C shows the cross-sectional view in a state where the stepsso far are completed.

Next, the frame body layer 70 coated on the upper electrodes 533 and 633is exposed and developed by a photolithography method to pattern theframe body layer 70 into a desired shape. In this step, the frame body64 and the second frame body 54 which have the cavities 54A and 64A andare independent of each other are formed (frame body forming step). FIG.6A shows the cross-sectional view in a state where the steps so far arecompleted.

Next, the silicone oil 20 is filled in the cavity 64A of the frame body64 of the pressure sensor 6 (filling step). FIG. 6B shows thecross-sectional view in a state where the steps so far are completed.

Next, a dry film resist corresponding to the protective film 55 and thesealing film 65 is coated on the upper surface of the frame body 64 andthe second frame body 54 using a roll coating apparatus (film formingstep). With this step, the inner space 66 is formed. FIG. 6C shows thecross-sectional view in a state where the steps so far are completed.

Next, the dry film resist corresponding to the protective film 55 andthe sealing film 65 is exposed and developed by a photolithographymethod to pattern the protective film 55 and the sealing film 65 into adesired shape. FIG. 7A shows the cross-sectional view in a state wherethe steps so far are completed.

Next, the lower surface side of the common supporting body 51, 61 is dryetched to form the opening 61A and the second opening 51A havingsubstantially the same dimensions as the inner diameter dimensions ofthe frame body 64 and the second frame body 54.

Through the steps described above, the sensor array 4 including theplurality of ultrasonic sensors 5 and the plurality of pressure sensors6 on the common supporting body 51, 61, shown in FIG. 7B, is formed.

According to the pressure sensor 6, the sensor array 4, and the methodfor manufacturing the sensor array 4 of the embodiment described above,the following advantageous effects are provided.

As shown in FIG. 3B, the piezoelectric body 63 of the membrane 8 iscontained in the frame body 64, and the silicone oil 20 which dispersesa force is filled in the inner space 66 of the frame body 64. The framebody 64 is sealed by the sealing film 65. According to thisconfiguration, when the arms 3 of the grasping apparatus 1 grasp theobject 10, the object 10 abuts on the sealing film 65, and a force inthis state is transmitted to the membrane 8 via the silicone oil 20.That is, since the object 10 does not directly contact the piezoelectricfilm 631 and a force when the object 10 contacts the sealing film 65 istransmitted to the membrane 8 via the silicone oil 20, the dispersedforce is applied to the diaphragm portion 67 of the membrane 8 whichdetects pressure. Accordingly, the local application of force to thediaphragm portion 67 can be prevented, which can prevent the breakage ofthe membrane 8.

As shown in FIG. 3B, since the frame body 64 is formed of a permanentresist made of a synthetic resin having flexibility, the frame body 64contracts when a force is applied to the frame body 64. The force istransmitted to the diaphragm portion 67 of the membrane 8 via thesilicone oil 20 filled in the inner space 66 of the frame body 64, sothat pressure can be favorably detected.

As shown in FIG. 2, the sensor array 4 includes two kinds of sensors,the pressure sensor 6 and the ultrasonic sensor 5. Therefore, thegrasping apparatus 1 including the sensor array 4 can recognize theobject 10 by the ultrasonic sensor 5 and detect pressure in a statewhere the arms 3 grasp the object 10 by the pressure sensor 6.

As shown in the method for manufacturing the sensor array, since it isonly necessary for the ultrasonic sensor 5 to be configured of theconstituent members constituting the pressure sensor 6 excepting thesilicone oil 20 and the sealing film 65, the ultrasonic sensor 5 can bemanufactured easily. That is, the ultrasonic sensor 5 can bemanufactured in the course of manufacturing the pressure sensor 6.Accordingly, the manufacturing steps of the sensor array 4 can besimplified, which can reduce the manufacturing cost.

In the case of configuring a sensor array having a portion where onlythe pressure sensor 6 is formed or a portion where only the ultrasonicsensor 5 is formed, a position at which the ultrasonic sensor 5recognizes the object 10 sometimes differs from a position at which thepressure sensor 6 detects a force grasping the object 10, which maycause a variation between detected positions of the sensors 5 and 6.

In the embodiment, on the other hand, since the pressure sensors 6 andthe ultrasonic sensors 5 are arranged at equal distances from each otheras shown in FIG. 2, a variation does not occur between the position atwhich the ultrasonic sensor 5 recognizes the object 10 and the positionat which the pressure sensor 6 detects the force grasping the object 10.

Since the ultrasonic sensor 5 and the pressure sensor 6 are arrangedindependently of each other, the transmission of vibrations of themembrane 8 of the ultrasonic sensor 5 to the pressure sensor 6 can besuppressed. That is, since the influence of vibrations from theultrasonic sensor 5 on the piezoelectric body 63 or the diaphragmportion 67 of the membrane 8 of the pressure sensor 6 is reduced, thepressure sensor 6 can detect pressure with good accuracy.

Hereinafter, another embodiment (second embodiment) according to theinvention will be described based on the drawings.

Second Embodiment Configuration of Sensor Array

FIG. 9 is a perspective view showing a sensor array 180 according to thesecond embodiment. FIG. 10A is a plan view of the sensor array 180 shownin FIG. 9; FIG. 10B is a cross-sectional view taken along line A-A′shown in FIG. 10A when the object 10 contacts the sensor array; and FIG.10C is a cross-sectional view taken along the line A-A′ when a greaterpressure than usual is applied in a state of grasping the object 10.

The sensor array 180 is, for example, a tactile sensor having excellentresistance to pressure and outputs, as an electric signal, pressurebetween the object 10 and the sensor array 180 as shown in FIGS. 10A to10C. The sensor array 180 includes a plurality of pressure sensors 106which are mounted on a supporting body 161. The sensor array 180 differsfrom the sensor array of the first embodiment in that a groove G as agap is arranged so that when a smaller pressure than an allowablepressure of the pressure sensor 106, near the allowable pressure, isapplied, frame bodies of the pressure sensors 106 next to each other arepushed (contacted) to each other to thereby function as each other'sreinforcing materials. Other than these points, the sensor array 180 issimilar to that described in the first embodiment. For example, thegroove G may be formed only at a portion between the pressure sensors106.

The pressure sensor 106 has the structure shown in “Configuration ofPressure Sensor” described above. That is, in FIG. 10B, since a membrane108 is subjected to pressure via a silicone oil 120 with a top of thepressure sensor 106 being as a pressure-sensitive surface (abutmentsurface), an impact from the object 10 can be dispersed over the entiremembrane 108. Since the membrane 108 is protected from the concentrationof pressure, the reliability of the pressure sensor 106 can be improved.

The pressure sensor 106 performs the operation shown in “Operation ofPressure Sensor” described above. That is, a piezoelectric film 731deflects by being subjected to pressure from the object 10, and voltageaccording to the deflection amount is generated. Thus, the pressure canbe detected based on the voltage generated from the membrane 108.

As shown in FIGS. 9 and 10B, in the sensor array 180, the pressuresensors 106 each of which has a frame body 164 whose outer shape is arectangle (square as an example in this case) are arranged, on asupporting body 161 which includes openings 121 and is provided incommon to the plurality of pressure sensors, along a predetermined firstdirection (X-direction) and a second direction (Y-direction)perpendicular to the first direction (X-direction) with the grooves Gall having the same width and each interposed between the pressuresensors. In other words, a gap for separating the frame bodies 164 fromeach other is formed between the frame bodies.

The width of the groove G will be described in “Operation of SensorArray” described later.

The pressure sensors 106 are arranged to be separated from each other sothat the supporting body 161 is exposed in the gap between the pressuresensors.

Although, in the preferred example shown in FIG. 9, the groove G isformed to the position of the surface of the supporting body 161, astructure in which a portion of the supporting body 161 is hollowed maybe used. Especially when silicon is used for the supporting body 161 andsilicon oxide or ZrO₂ is used for a supporting film 162, high shapereproducibility can be provided because a high selectivity is obtainedwhen performing etching.

Moreover, a configuration having a groove G formed to such a depth thatthe supporting film 162 is exposed may be used. In this case, especiallywhen a permanent resist is used for the frame body 164, high shapereproducibility can be provided because etching is stopped by thesupporting film 162. Moreover, since etching can be performed using adeveloper at the same time as when the frame body 164 is fabricated, themanufacturing steps can be shortened.

Moreover, it is allowed for the groove G to use a structure in which aframe body layer 170 made of a permanent resist used for forming theframe body 164 is thinly left at the bottom of the groove on thesupporting body side. In this case, a processing method for obtainingthe configuration described above is described. However, this does notintend to limit a processing method but is introduced as an example forobtaining the structure. Irrespective of a processing method, it issufficient to have the shape described above. Moreover, the pressuresensors 106 may be divided into individual ones (edge cutting) and maybe arranged again on a sensor substrate (not shown) which is preparedseparately. Moreover, a sensor substrate may be bonded to the supportingbody 161 and may be cut (edge cutting) to the supporting body 161. Inthis case, since interference between the pressure sensors 106 can beprevented, pressure can be measured with higher accuracy.

The term “edge cutting” as used herein includes, in addition to the caseof complete separation, the case where the pressure sensors are notcompletely separated but connected to such an extent that they do notcause functional interference.

Operation of Sensor Array

Next, the operation of the sensor array 180 will be described withreference to FIGS. 1 and 10A to 10C. The sensor array 180 (not shown inFIG. 1) is described as being bonded to the grasping surface 31 in thiscase.

First, when the object 10 contacts the grasping surface 31 as shown inFIG. 10B, the pressure sensor 6 detects pressure given to the object 10.By applying pressure from the grasping surface 31 to the object 10, theobject 10 is grasped.

When too much stress is applied to the pressure sensor 106, the pressuresensor 106 may be excessively collapsed and deteriorated. When excessivepressure is applied to the pressure sensor 106, the frame body 164deforms such that the central portion expands more than both ends withrespect to the height direction of the frame body, the region formed byseparation with the groove G is filled, and the frame body 164 and theframe body of the next pressure sensors 106 are pushed to each other. Asshown in FIG. 10C, therefore, the pressure sensors 106 next to eachother function as each other's reinforcing materials, which can preventthe deterioration of the pressure sensor 106 caused by excessivecollapse. In other words, the width of the groove G is preferably such awidth that the frame bodies 164 contact each other when pressure lessthan a breaking strength is applied.

Method for Manufacturing Sensor Array

Next, a method for manufacturing the sensor array 180 including thepressure sensors 106 will be described.

FIGS. 11A to 12D are step cross-sectional views for explainingmanufacturing steps for manufacturing the plurality of pressure sensors106.

First, a single-crystal silicon substrate which serves as the supportingbody 161 (a thickness of about 650 μm) is prepared, and the surface ofthe substrate is thermally oxidized, so that a first oxide film 162Aformed of SiO₂ is formed so as to have a thickness of about 1 μm. Bydepositing Zr by sputtering and thermally oxidizing the same, ZrO₂ isformed on the first oxide film 162A. A second oxide film 162B formed ofZrO₂ is formed so as to finally have a thickness of about 3 μm, wherebythe supporting film 162 is formed. FIG. 11A shows the stepcross-sectional view in a state where the step so far is completed.

In this case, when the groove G is formed to a portion of the supportingbody 161 between the pressure sensors 106, a step of forming the grooveG is preferably performed in this state where the supporting film 162 isformed, in view of the manufacturing steps. In the embodiment, the caseof using, in a later step than this step, the step of forming the grooveG by which the supporting body 161 is exposed and the supporting film162 is divided will be described. The groove G is formed at a positionoverlapping with the gap between the pressure sensors 106.

Next, in an argon gas atmosphere under a predetermined pressure, aconductor film constituting a lower electrode 732 is formed so as tocover the second oxide film 162B using sputtering deposition. Anot-shown photoresist is coated on the surface side of the supportingbody 161 where the supporting film 162 is formed, and exposed anddeveloped by a photolithography method. Further by an etching process,the lower electrode 732 is patterned.

FIG. 11B shows the step cross-sectional view in a state where the stepsso far are completed.

Next, a film for forming the piezoelectric film 731 is deposited bysputtering so as to cover the lower electrode 732. By a photolithographymethod and an etching process, the piezoelectric film 731 is patterned.The piezoelectric film 731 functions as a pressure detecting portion.

FIG. 11C shows the step cross-sectional view in a state where the stepsso far are completed.

Next, on the surface side of the supporting body 161 where the lowerelectrode 732 is arranged, a conductor film constituting an upperelectrode 733 is deposited by a sputtering method. By a photolithographymethod and an etching process, the upper electrode 733 is patterned toform a plurality of island-like piezoelectric bodies 163. Thus,island-like pressure detecting portions 175 (including the supportingfilm 162 and the piezoelectric body 163) are formed. The term“island-like pressure detecting portion” as used herein means that theshape of a region where four layers of the supporting film, the lowerelectrode, the piezoelectric film, and the upper electrode are stackedis an independent island-like shape (pressure detecting portion formingstep). Next, the groove G which divides the supporting film 162 isformed (groove forming step).

FIG. 11D shows the step cross-sectional view in a state where the stepsso far are completed.

Next, the supporting body 161 is grinded by, for example, back grinding(BG) so that the thickness is reduced to about 200 μm. This is becausewhen the supporting body 161 which has been grinded to a desiredthickness dimension is prepared in the steps so far, the supporting body161 may be warped during the manufacturing steps.

FIG. 11E shows the step cross-sectional view in a state where the stepsso far are completed.

Next, a permanent resist is coated as the frame body layer 170 on theupper electrodes 733 using a spin coating apparatus or a squeegee. Thus,the frame body layer 170 is formed so as to cover the piezoelectricbodies 163 (frame body layer forming step).

FIG. 11F shows the step cross-sectional view in a state where the stepsso far are completed.

If the groove G is formed in a step after forming the frame body layer170, the frame body layer 170 may be damaged. Therefore, the groove G ispreferably formed in the steps so far. Specifically, the groove G may beprocessed such that a region whose thickness is thin is provided betweenthe frame bodies 164 next to each other using the same material as theframe body 164, that a region where the piezoelectric body 163 isexposed is provided between the frame bodies 164 next to each other,that a region where the supporting body 161 is exposed is providedbetween the frame bodies 164 next to each other (in the case of theembodiment), or that a region where the supporting body 161 is exposedand further the supporting body 161 is hollowed is provided between theframe bodies 164 next to each other. If the damage of the frame bodylayer 170 can be prevented even when the groove G is formed, the step offorming the groove G may be performed in a later step.

The frame body layer 170 (permanent resist) coated on the upperelectrodes 733 is exposed and developed by a photolithography method topattern the frame body layer 170 such that the outer shape of a regionto serve as the frame body 164 of the frame body layer 170 is arectangle (square as an example in this case) as shown in FIGS. 10A to10C, and to pattern the frame body layer 170 so as to form a cavity 164Ato expose a detecting portion 175 inside the region to serve as theframe body 164, whereby the plurality of frame bodies 164 are formed(frame body forming step). FIG. 11G shows the step cross-sectional viewin a state where the steps so far are completed.

In the cavity 164A of the frame body 164, the silicone oil 120 as apressure medium is filled (filling step). Any material can be used forthis as long as the material disperses pressure. Other than the siliconeoil 120, for example, a silicone rubber, a polymer gel, a synthetic gel,a natural gel, a polymer resin, or the like may be used.

FIG. 11H shows the step cross-sectional view in a state where the stepsso far are completed.

Next, a dry film resist 165A is coated as a sealing film on the uppersurface of the frame body 164 by a roll coating apparatus (film formingstep). Thus, the cavity 164A is sealed to serve as an inner space 166.FIG. 12A shows the step cross-sectional view in a state where the stepsso far are completed.

In this case, for coating without including air bubbles, coating ispreferably performed in a reduced-pressure atmosphere. Moreover, forclosely adhering the resist 165A, coating is preferably performed whileheating.

Next, patterning is performed so as to leave the resist 165A located ata region overlapping with the frame body 164 and inside the frame body164, whereby a sealing film 165 as a pressure-sensitive film serving asa pressure-sensitive surface is formed. FIG. 12B shows the stepcross-sectional view in a state where the steps so far are completed.

Next, the surface (back surface) of the supporting body 161 where thesupporting film 162 is not present is dry etched such that, in plan viewof the supporting body 161, an opening is substantially overlapped withan opening inside the frame body 164. Then, an opening 161A is formed soas to substantially overlap with the opening inside the frame body 164.FIG. 12C shows the step cross-sectional view in a state where the stepsso far are completed.

By completing the steps so far, the sensor array 180 including thepressure sensors 106 is formed.

In addition to the steps of the manufacturing method described above, astep of bonding a sensor substrate 45D to the supporting body 161,cutting the supporting body 161, and separating the pressure sensors 106may be added. In this case, a structure shown in FIG. 12D can beobtained. That is, the pressure sensor 106 is supported by the sensorsubstrate 45D.

Moreover, the supporting body 161 may be first cut and then bonded tothe sensor substrate 45D.

According to the configuration of the pressure sensor 106, theconfiguration of the sensor array 180, and the method for manufacturingthe sensor array 180 of the embodiment described above, the followingadvantageous effects can be obtained.

When excessive pressure is applied to the pressure sensor 106, the framebody 164 deforms such that the central portion expands more than bothends with respect to the height direction of the frame body, the grooveG is filled, and the frame body 164 and the frame body of the nextpressure sensor 106 are pushed to each other. As shown in FIG. 10C,therefore, the pressure sensors 106 next to each other function as eachother's reinforcing materials, which can prevent the deterioration ofthe pressure sensor 106 caused by excessive collapse.

The pressure sensors 106 each of which has the frame body 164 whoseouter shape is a rectangle (square as an example in this case) arearranged along the predetermined first direction (X-direction) and thesecond direction (Y-direction) perpendicular to the first direction(X-direction) with the grooves G all having the same value. Therefore,when excessive pressure is applied to the pressure sensors 106, theframe bodies 164 next to each other are pushed to each other at a plane.Therefore, compared to the case where the outer shape of the frame body164 is, for example, circular or the like, since the frame bodies 164next to each other are pushed to each other at a plane, resistance tohigh pressure can be further improved, making it possible to provide thesensor array 180 with high reliability.

After performing the manufacturing process to a certain extent, the stepof grinding the supporting body 161 by, for example, back grinding (BG)so that the thickness is reduced to about 200 μm is used. Therefore, itis possible to suppress the occurrence of such a defect that thesupporting body 61 is warped during the manufacturing steps.

Hereinafter, still another embodiment (third embodiment) according tothe invention will be described based on the drawings.

Third Embodiment Configuration of Sensor Array

FIG. 13 is a perspective view showing a sensor array 281. FIG. 14A is aplan view of the sensor array 281 shown in FIG. 13; and FIG. 14B is across-sectional view taken along line A-A′ of the plan view shown inFIG. 14A. The sensor array 281 includes ultrasonic sensors 205 inaddition to pressure sensors 206.

The sensor array 281 is, for example, a tactile sensor which can detectdistance information and pressure information. The sensor array 281includes the plurality of ultrasonic sensors 205 each of which outputsdistance information as an electric signal when the object 10 is awayfrom the sensor array 281, and the plurality of pressure sensors 206each of which outputs, as an electric signal, the pressure between theobject 10 and the sensor array 281 when the object 10 contacts thesensor array 281. The sensor array 281 differs from the sensor array 180in the second embodiment (for example, refer to FIGS. 10A and 10B) inincluding the plurality of ultrasonic sensors 205 in addition to theplurality of pressure sensors 206 mounted on a common supporting body251, 261.

The sensor array 281 has such features that a top of the pressure sensor206 based on the common supporting body 251, 261 is formed so as to bepositioned high compared to a top of the ultrasonic sensor 205, and thatthe pressure sensor 206 and the ultrasonic sensor 205 are arranged via agroove K as a predetermined gap so that when a smaller pressure than anallowable pressure of the sensor array 281, near the allowable pressure,is applied, the pressure sensor 206 and the ultrasonic sensor 205 arepushed (contacted) to the next pressure sensor 206 or the nextultrasonic sensor 205 to thereby function as each other's reinforcingmaterials. Other than these points, the sensor array 281 is similar tothose described in the first embodiment and the second embodiment. Forexample, the groove K may be formed only at a portion between thepressure sensor 206 and the ultrasonic sensor 205.

By including the ultrasonic sensor 205, even in a state where the arm 3of the grasping apparatus 1 (refer to FIG. 1) is away from the object10, the distance between the arm and the object 10 can be measured.Therefore, it is possible to grasp the object 10 with higher speed andprecision. For example, since the distance between the arm and theobject 10 can be measured, the arms 3 are moved at high speed until theycontact the object 10, and a grasping state is maintained by thepressure sensors 206 after contact, thereby making it possible to graspthe object 10 in a state of maintaining the accuracy of graspingpressure.

The ultrasonic sensor 205 has the structure shown in “Configuration ofUltrasonic Sensor” described above. That is, as shown in FIG. 3A, thesecond diaphragm portion 57 which can perform free vibrations isprovided, and the piezoelectric film 731 using PZT or the like isconnected to the second diaphragm portion 57. The lower electrode 732and the upper electrode 733 which apply voltage to the piezoelectricfilm 731 are provided.

The ultrasonic sensor 205 performs the operation shown in “Operation ofUltrasonic Sensor” described above. That is, a second diaphragm portion207B is vibrated in a direction perpendicular to the plane direction ofa second supporting film 252 by the application of voltage to transmitultrasonic waves at a frequency according to a predetermined drivevoltage cycle. By receiving reflected waves from the object 10 (refer toFIG. 1), the position of the object 10 is detected.

In the sensor array 281, on the integrated supporting body 251, 261, theultrasonic sensors 205 and the pressure sensors 206 which have a secondframe body 254 and a frame body 264, respectively, whose outer shape isa rectangle (square as an example in this case) are alternately arrangedwith a predetermined gap (width of the groove K) along a predeterminedfirst direction (X-direction) and a second direction (Y-direction)perpendicular to the first direction (X-direction). The width of thegroove K will be described in “Grasping Apparatus including SensorArray” described later.

The ultrasonic sensor 205 is formed such that a top of the ultrasonicsensor 205 based on the common supporting body 251, 261 is positionedlow by the thickness of a sealing film 265 compared to a top of thepressure sensor 206. In this case, the difference between the toppositions is not essentially limited to the thickness of the sealingfilm 265, and an ultrasonic sensor 205 having a top lower than the topof the pressure sensor 206 may be provided.

The ultrasonic sensor 205 and the pressure sensor 206 are separatelyarranged so that the common supporting body 251, 261 is exposed in thegap between the ultrasonic sensor 205 and the pressure sensor 206.

Instead of having the shape of exposing a portion of the commonsupporting body 251, 261, a structure in which the common supportingbody 251, 261 is hollowed may be used as a structure of the groove K.Especially when silicon is used for the common supporting body 251, 261and silicon oxide or ZrO₂ is used for a common supporting film 252, 262,high shape reproducibility can be provided.

Moreover, a step of forming the groove K to such a depth that the commonsupporting film 252, 262 is exposed may be used. In this case,especially when a permanent resist is used for the frame body 264 andthe second frame body 254, high shape reproducibility can be providedbecause etching is stopped by the common supporting film 252, 262.Moreover, since etching can be performed using a developer at the sametime as when the frame body 264 and the second frame body 254 arefabricated, the manufacturing steps can be shortened.

Moreover, it is allowed for the groove K to use a structure in which aframe body layer 270 made of a permanent resist used for forming theframe body 264 and the second frame body 254 is thinly left at thebottom of the groove on the supporting body side. In this case, aprocessing method for obtaining the configuration described above isdescribed. However, this does not intend to limit a processing methodbut is introduced as an example for obtaining the structure.Irrespective of a processing method, it is sufficient to have the shapedescribed above.

Method for Manufacturing Sensor Array

Next, a method for manufacturing a sensor array will be described. Inthis case, the ultrasonic sensor 205 and the pressure sensor 206 areformed on the same substrate (the common supporting body 251, 261).FIGS. 16A to 17D are step cross-sectional views for explainingmanufacturing steps of the sensor array.

First, a single-crystal silicon substrate which serves as the commonsupporting body 251, 261 (a thickness of about 650 μm) is prepared, andthe surface of the substrate is thermally oxidized, whereby the firstoxide film 252A, 262A formed of SiO₂ is formed so as to have a thicknessof about 1 μm. By depositing Zr by sputtering and thermally oxidizingthe same, a second oxide film 252B, 262B formed of ZrO₂ is formed on thefirst oxide film 252A, 262A so as to have a thickness of about 3 μm,whereby the common supporting film 252, 262 is formed. FIG. 16A showsthe step cross-sectional view in a state where the steps so far arecompleted.

When the groove K is formed to a portion of the common supporting body251, 261 between the ultrasonic sensor 205 and the pressure sensor 206,a step of forming the groove K is preferably performed in this statewhere the common supporting film 252, 262 is formed, in view of themanufacturing steps. In the embodiment, the case of using, in a laterstep than this step, the step of forming the groove K to expose thecommon supporting body 251, 261 will be described.

Next, in an argon gas atmosphere under a predetermined pressure, aconductor film constituting lower electrodes 932 and 832 is formed so asto cover the second oxide film 252B, 262B using sputtering deposition. Aphotoresist is coated on the surface side of the common supporting body251, 261 where the common supporting film 252, 262 is formed, is exposedand developed by a photolithography method, and is further patterned byan etching process to form the lower electrodes 932 and 832. Thispatterning is performed such that when a predetermined pressure equal toor less than an allowable pressure is applied to the pressure sensor206, the groove K where the pressure sensor 206 contacts the nextpressure sensor 206 or the next ultrasonic sensor 205 is obtained in thegap between the pressure sensors 206 as finished articles or the gapbetween the ultrasonic sensor 205 and the pressure sensor 206 asfinished articles.

FIG. 16B shows the step cross-sectional view in a state where the stepsso far are completed.

Next, a film for forming a piezoelectric film 931 and a secondpiezoelectric film 831 is deposited by sputtering so as to cover thelower electrodes 932 and 832. By patterning by a photolithography methodand an etching process, the piezoelectric film 931 and the secondpiezoelectric film 831 are formed. The piezoelectric film 931 and thesecond piezoelectric film 831 function as a pressure detecting portionand an ultrasonic transducer portion, respectively.

FIG. 16C shows the step cross-sectional view in a state where the stepsso far are completed.

Next, on the surface side of the common supporting body 251, 261 wherethe lower electrodes 932 and 832 are arranged, a conductor filmconstituting upper electrodes 933 and 833 is deposited by sputtering. Bypatterning by a photolithography method and an etching process, theupper electrodes 933 and 833 are obtained, and a piezoelectric body 263and a second piezoelectric body 253 each having an island-like shape areformed. Thus, a plurality of island-like ultrasonic transducer portions275 (including the second supporting film 252 and the secondpiezoelectric body 253) and a plurality of island-like pressuredetecting portions 285 (including the supporting film 262 and thepiezoelectric body 263) are formed. The terms “island-like ultrasonictransducer portion” and “island-like pressure detecting portion” as usedherein mean that the shape of a region where four layers of thesupporting film, the lower electrode, the piezoelectric film, and theupper electrode are stacked is an independent island-like shape(piezoelectric body sensor portion forming step).

Next, the groove K which divides the common supporting film 252, 262 isformed (groove forming step).

FIG. 16D shows the step cross-sectional view in a state where the stepsso far are completed.

Next, the common supporting body 251, 261 is grinded by, for example,back grinding (BG) so that the thickness is reduced to about 200 μm.This is because when the common supporting body 251, 261 which has beengrinded to a desired thickness dimension is prepared in the steps sofar, the common supporting body 251, 261 may be warped during themanufacturing steps.

FIG. 16E shows the step cross-sectional view in a state where the stepsso far are completed.

Next, a permanent resist is coated as a frame body layer 270 on theupper electrodes 933 and 833 using a spin coating apparatus or asqueegee and dried. Thus, the frame body layer 270 is formed so as tocover the piezoelectric body 263 and the second piezoelectric body 253(frame body layer forming step).

FIG. 16F shows the step cross-sectional view in a state where the stepsso far are completed.

If the groove K is formed in a step after forming the frame body layer270, the frame body layer 270 may be damaged. Therefore, the groove K ispreferably formed in the steps so far. Specifically, the groove Kincludes a region which is formed using the same material as the framebody layer 270 and whose thickness is thin between the frame body 264and the second frame body 254 next to each other. Alternatively, thegroove K may include a region where the piezoelectric body 263 and thesecond piezoelectric body 253 are exposed between the frame body 264 andthe second frame body 254 next to each other. Alternatively, the grooveK may include a region where the common supporting body 251, 261 isexposed between the frame body 264 and the second frame body 254 next toeach other (the case of the embodiment). Alternatively, the groove K maybe processed so as to include a region where the common supporting body251, 261 is exposed and further the common supporting body 251, 261 ishollowed between the frame body 264 and the second frame body 254 nextto each other. If the damage of the frame body layer 270 can beprevented even when the groove K is formed, the step of forming thegroove K may be performed in a later step.

The frame body layer 270 formed on the upper electrodes 833 and 933 isexposed and developed by a photolithography method to pattern the framebody layer 270 such that the outer shape of the regions to serve as theframe body 264 and the second frame body 254 of the frame body layer 270is a rectangle (square as an example in this case), and to pattern theframe body layer 270 so as to form a cavity 254A and a cavity 264A toexpose the ultrasonic transducer portion 275 and the pressure detectingportion 285 inside the regions to serve as the frame body 264 and thesecond frame body 254, whereby a plurality of frame bodies 264 andsecond frame bodies 254 are formed (frame body forming step). FIG. 16Gshows the step cross-sectional view in a state where the steps so farare completed.

Next, in the cavity 264A of the frame body 264 which finally serves asthe pressure sensor 206, a silicone oil 220 is filled (filling step). Inthis case, the silicone oil 220 is not filled in the cavity 254A of thesecond frame body 254 which finally serves as the ultrasonic sensor 205.FIG. 17A shows the step cross-sectional view in a state where the stepsso far are completed.

Next, a dry film resist is coated as a sealing film 265A on the uppersurface of the frame body 264 and the second frame body 254 by a rollcoating apparatus (film forming step). Thus, the cavity 264A is sealedto serve as an inner space 266. In this case, for coating withoutincluding air bubbles, coating is preferably performed in areduced-pressure atmosphere. Moreover, for closely adhering the resist265A, coating is preferably performed while heating. It is not necessaryto form the sealing film 265A for the second frame body 254. However,since it is technically difficult to selectively form a dry film resistas the sealing film 265A using a roll coating apparatus, such a processthat the sealing film 265A is once formed and then removed is performedas will be described later.

FIG. 17B shows the step cross-sectional view in a state where the stepsso far are completed.

Next, patterning is performed so as to leave the sealing film 265located at a region overlapping with the frame body 264 and inside theframe body 264 to selectively remove the sealing film 265A. FIG. 17Cshows the step cross-sectional view in a state where the steps so farare completed.

Next, the surface (back surface) of the common supporting body 251, 261on the side where the second supporting film 252 and the supporting film262 are not present is dry etched such that, in plan view of the commonsupporting body 251, 261, openings are substantially overlapped with theopenings inside the frame body 264 and the second frame body 254. Then,a second opening 251A and an opening 261A having substantially the samedimensions as the inner diameter dimensions of the frame body 264 andthe second frame body 254 are formed so as to overlap with the openingsinside the frame body 264 and the second frame body 254, whereby theultrasonic sensor 205 and the pressure sensor 206 are formed. FIG. 17Dshows the step cross-sectional view in a state where the steps so farare completed.

By completing the steps so far, the sensor array 281 is formed.

After completing the manufacturing steps described above, a sensorsubstrate (not shown) may be bonded to the common supporting body 251,261 side, and the common supporting body 251, 261 positioned in the gapbetween the pressure sensors 206, the gap between the ultrasonic sensors205, and the gap between the pressure sensor 206 and the ultrasonicsensor 205 may be cut by means such as etching. In this case, thetransmission of vibrations is suppressed between the pressure sensor 206and the ultrasonic sensor 205 by the sensor substrate. Therefore, thesensor array 281 which can precisely measure pressure is obtained.

Grasping Apparatus including Sensor Array

Next, the operation of the grasping apparatus 1 including the sensorarray 281 will be described using FIGS. 22 to 24. FIG. 22 is a blockdiagram for explaining a grasping operation of the grasping apparatus 1;FIG. 23 is a flowchart for explaining the grasping operation of thegrasping apparatus 1; and FIGS. 24A to 24C are timing diagrams forexplaining the grasping operation of the grasping apparatus 1.

FIG. 22 is a block diagram where a control device and a drive mechanismblock of the grasping apparatus 1, which are not shown in FIG. 1, areadditionally illustrated. Similarly to the illustration in FIG. 1, thegrasping apparatus 1 includes the supporting member 2 and the pair ofarms 3 as grasping arms which extend from the supporting member 2. Thearms 3 grasp the object 10. On the grasping surface 31 with which thearm 3 contacts the object 10, any of the sensor array 4 (refer to FIG.2), the sensor array 281 (refer to FIG. 13), and a sensor array 481(refer to FIG. 20) may be attached. In the embodiment, the case wherethe sensor array 281 is attached will be described.

As shown in FIG. 22, the grasping apparatus 1 includes a control device104 for drivingly controlling the arms 3, and a drive mechanism 105.

The control device 104 includes a signal detecting unit 101, a graspdetecting unit 102, and a drive control unit 103.

The signal detecting unit 101 detects a distance signal from, forexample, the ultrasonic sensor 205 (refer to FIGS. 14A and 14B) when theobject 10 is away from the sensor array 281.

The grasp detecting unit 102 detects a pressure signal from the object10 and the pressure sensor 206 (refer to FIGS. 14A and 14B) of thesensor array 281 provided on the grasping surface 31.

In the embodiment, the signal detected from the signal detecting unit101 and the signal detected from the grasp detecting unit 102 aretransmitted to the drive control unit 103. When the object 10 is awayfrom the sensor array 281, the signal detected from the signal detectingunit 101 (the ultrasonic sensor 205) is transmitted to the drivemechanism 105 described later. When the object 10 is in contact with thesensor array 281, the pressure signal detected from the grasp detectingunit 102 (for example, the pressure sensor 206) is transmitted from thedrive control unit 103 to the drive mechanism 105. Although, in thiscase, an example in which the distance signal and the pressure signalare output as digital signals is shown, also analog signal output can besimilarly processed. For example, control may be performed using an OPamplifier or the like, or signals may be processed by AD conversion.

The drive mechanism 105 includes a power source 116 and a powertransmitting portion 117.

The power source 116 is, for example, a motor. To the motor, a signal(control signal) for controlling the rotational speed is transmittedfrom the drive control unit 103. When it is sufficient that the object10 and the sensor array 281 satisfy a poor positional accuracy (they aresufficiently away from each other), a signal to keep the rotationalspeed of the motor constant is transmitted from the drive control unit103.

When the object 10 and the sensor array 281 require a precise positionalaccuracy, that is, when they are approaching each other, a signal toreduce the rotational speed of the motor is transmitted from the drivecontrol unit 103. A set distance (PC) 109 for changing the rotationalspeed of the motor is previously written as a data table in a memory 118included in the control device 104. That is, the set distance (PC) 109is a threshold value for changing the driving speed and is appropriatelyset according to the size of the grasping apparatus 1 or the form of theobject 10.

When the pressure signal just corresponds with the value (set pressure(SP) 110) at which the grasping of the object 10 can be performed, themotor is stopped and the position of the arms 3 is kept. Also the setpressure for stopping the motor is previously written in the memory 118included in the control device 104.

The power transmitting portion 117 converts mechanical outputtransmitted from the power source 116 to the grasping movement of thearms 3 with a not-shown gear or the like.

Subsequently, graphs (timing diagrams) of FIGS. 24A to 24C will bedescribed.

In the graphs shown in FIGS. 24A to 24C, the horizontal axes (X-axes)are taken as time axes showing the same time series for the graphs A, B,and C. Hereinafter, each of the graphs will be described.

FIG. 24A is a graph showing a relation between the moving speed (speedof grasping operation) of the arm 3 and time. The vertical axis (Y-axis)of the graph shown in FIG. 24A shows the moving speed (speed of graspingoperation: SA) and direction of the arm 3, in which the positive value(positive direction of Y-axis) shows that the arm 3 moves in a directionapproaching the object 10.

The speed of grasping operation is divided into three levels in theembodiment: a constant speed (CS) when remote (R) 111; a low speed (LS)in proximity detection (PP) 112; and the speed of a microoperation (SS)in a grasping operation (MS) 113.

FIG. 24B is a graph showing a relation between the distance between theultrasonic sensor 205 and the object 10, and time. The vertical axis(Y-axis) of the graph shown in FIG. 24B is a distance signal (DS)showing the distance between the ultrasonic sensor 205 and the object10. When the ultrasonic sensor 205 contacts the object 10, 0 is outputin principle.

FIG. 24C is a graph showing a relation between the pressure signal ofthe pressure sensor 206 and time. The vertical axis (Y-axis) of thegraph shown in FIG. 24C is a pressure signal (PS) showing the pressurebetween the pressure sensor 206 and the object 10. When the pressuresensor 206 is away from the object 10, 0 is output in principle.

FIG. 23 is a flowchart showing a flow of a grasping method. Next, thegrasping operation by the grasping apparatus 1 will be describedaccording to the flowchart shown in FIG. 23. An operation in each stepis executed based on the control signal from the control device 104described above.

In Step S1, when the grasping surfaces 31 of the arms 3 as grasping armsshown in FIG. 22 are remote from the object 10 (the distance between thegrasping surface 31 and the object 10 is greater than the set distance(PC) 109 described above), an operation to bring the arms 3 close to theobject 10 is performed at uniform speed (constant speed (CS)) as shownin FIG. 24A.

This operation is applied when the distance signal shown in FIG. 24B isequal to or greater than the set distance (PC) 109 described above,which shows a state before TO in the timing diagrams in FIGS. 24A to24C.

In Step S2, it is determined based on a distance signal detected by theultrasonic sensor 205 whether the distance between the grasping surface31 and the object 10 is less than the set distance (PC) 109. If thedistance signal between the arm 3 and the sensor array 281 is less thanthe set distance (PC) 109 described above, the process proceeds to StepS3. If the distance signal is the set distance or greater, the processreturns to Step S1. This operation corresponds to T0-T1 in the timingdiagrams in FIGS. 24A to 24C.

In Step S3, the driving speed of the arm 3 is reduced to the low speed(LS). By reducing the speed, the distance between the arm 3 and theobject 10 can be adjusted more precisely. This operation corresponds toT1-T3 in the timing diagrams in FIGS. 24A to 24C.

In Step S4, the contact between the grasping surface 31 and the object10 is determined based on the pressure signal detected by the graspdetecting unit 102.

If the grasping surface 31 is not in contact with the object 10, thedriving speed reduced in Step S3 is maintained.

If contact detection (CD) between the grasping surface 31 and the object10 is made, the process proceeds to Step S5. This operation correspondsto T3-T4 in the timing diagrams in FIGS. 24A to 24C.

In Step S5, based on the pressure signal detected by the grasp detectingunit 102, the arms 3 shown in FIG. 22 are caused to perform themicrooperation (SS) to finely adjust pressure given to the object 10.This operation corresponds to T4-T5 in the timing diagrams in FIGS. 24Ato 24C.

In Step S6, determination is made based on a high and low relationbetween pressure received by the pressure sensor 206 and the setpressure (SP) 110 set with a range from a lower limit pressure to anupper limit pressure. If the pressure received by the pressure sensor206 is lower than the lower limit pressure of the set pressure (SP) 110,the process returns to Step S5. If the pressure of the pressure sensor206 is higher than the upper limit pressure of the set pressure 110,Step S8 is executed. If the pressure received by the pressure sensor 206falls between the lower limit pressure and the upper limit pressure, theprocess proceeds to Step S7. This operation corresponds to T5-T9 in thetiming diagrams in FIGS. 24A to 24C.

In Step S7, press control is stopped, and a holding operation isperformed. This operation corresponds to T9 or later in the timingdiagrams in FIGS. 24A to 24C.

By performing the above operations, the grasping apparatus 1 can graspthe object 10 at high speed with a highly accurate pressure.

During the holding operation, since the pressure sensor 206 differs fromthe ultrasonic sensor 205 in height by the thickness of the sealing film265, the ultrasonic sensor 205 does not contact the object 10 even whenthe pressure sensor 206 is slightly compressed by pressure. Therefore,in a usual grasping state, the ultrasonic sensor 205 can escapedeterioration due to pressure, thereby maintaining high reliability.

In this case, when the deformation of the frame body 264 of the pressuresensor 206 is increased (strongly grasping state) with an abnormallyincreased pressure due to some factors, the groove K is filled, and theframe body 264 of the pressure sensor 206 contacts the second frame body254 of the ultrasonic sensor 205, as shown in FIGS. 14B and 15A. By thecontact of the frame body 264 with the second frame body 254, thecharacteristics of the ultrasonic sensor 205 change.

That is, the width of the groove K is preferably set such that whenpressure having a smaller value than the allowable pressure, near theallowable pressure of the pressure sensor 206, is applied, the framebody 264 contacts the second frame body 254 of the ultrasonic sensor205. By providing such a width, the reliability of the pressure sensor206 can be improved.

Moreover, when too much pressure equal to or greater than the allowablepressure is applied to the pressure sensor 206 in a short time, acontrol signal from the ultrasonic sensor 205 is delayed, and thepressure sensor 206 may be excessively collapsed and deteriorated. Whenexcessive pressure is applied to the pressure sensor 206 and thepressure sensor 206 is deformed in the thickness direction by thethickness of the sealing film 265 (difference between the tops) or more,the ultrasonic sensor 205 starts deforming such that the central portionexpands more than both ends with respect to the height direction of thesecond frame body 254. Therefore, as shown in FIG. 15B, the pressuresensor 206 and the ultrasonic sensor 205 next to each other function aseach other's reinforcing materials, which can prevent the deteriorationof the pressure sensor 206 or the ultrasonic sensor 205 caused byexcessive collapse.

According to the configuration of the pressure sensor, the method formanufacturing the sensor array, and the grasping apparatus including thesensor array of the embodiment described above, the followingadvantageous effects can be provided.

Since the pressure sensor 206 differs from the ultrasonic sensor 205 inheight by the thickness of the sealing film 265, the ultrasonic sensor 5does not contact the object 10 even when the pressure sensor 206 isslightly compressed. Therefore, in a usual grasping state, theultrasonic sensor 205 can escape deterioration due to pressure, therebymaintaining high reliability.

When the deformation of the frame body 264 of the pressure sensor 206 isincreased, the groove K is filled, and the frame body 264 of thepressure sensor 206 contacts the second frame body 254 of the ultrasonicsensor 205. By the contact of the frame body 264 with the second framebody 254, the characteristics of the ultrasonic sensor 205 change. Inthis case, by setting the groove K such that when the pressure sensor206 is deformed within the elastic limit thereof, the frame body 264contacts the second frame body 254 of the ultrasonic sensor 205, thereliability of the pressure sensor 206 can be improved.

When excessive pressure is applied to the pressure sensor 206 and thepressure sensor 206 deforms in the thickness direction by the thicknessof the sealing film 265 or more, the ultrasonic sensor 205 startsdeforming such that the central portion expands more than both ends withrespect to the height direction of the second frame body 254. Therefore,the pressure sensor 206 and the ultrasonic sensor 205 next to each otherfunction as each other's reinforcing materials, which can prevent thedeterioration of the pressure sensor 206 or the ultrasonic sensor 205caused by excessive collapse.

Patterning is performed so as to leave the sealing film 265 located atthe region overlapping with the frame body 264 and inside the frame body264 to selectively remove the sealing film 265A, whereby the height ofthe second frame body 254 can be different from that of the frame body264, making it possible to form the pressure sensor 206 and theultrasonic sensor 205 including a step portion without increasing thenumber of manufacturing steps.

By performing the grasping operation according to the flowchart shown inFIG. 22, the grasping apparatus 1 can grasp the object 10 at high speedwith highly accurate pressure.

Hereinafter, further another embodiment (fourth embodiment) according tothe invention will be described based on the drawings.

Fourth Embodiment Configuration of Sensor Array

FIG. 25 is a cross-sectional view showing a sensor array 4C according tothe fourth embodiment. The sensor array 4C includes a sensor substrate45C which supports an ultrasonic sensor 5C and a pressure sensor 6C.

The ultrasonic sensor 5C and the pressure sensor 6C includethrough-electrodes 41C in a second supporting body 51C and a supportingbody 61C, respectively, and a wiring 43C provided on the sensorsubstrate 45C is connected to the through-electrodes 41C, whereby theultrasonic sensor and the pressure sensor are electrically conducted toa not-shown control portion via the wiring. A gap is provided betweensecond frame bodies 54C, between frame bodies 64C, and between thesecond frame body 54C and the frame body 64C. A groove LB as a gap isprovided between the second supporting body 51C and the supporting body61C. With the groove LB, edge cutting is performed between theultrasonic sensors next to each other, between the pressure sensors nextto each other, and between the ultrasonic sensor and the pressure sensornext to each other, whereby they are divided (independent). As will bedescribed below, the sensor array 4C is similar to that of the firstembodiment described above except for including the sensor substrate 45Cand including the groove LB between the second supporting body 51C andthe supporting body 61C. Moreover, a common supporting body may be usedfor the second supporting body 51C and the supporting body 61C.

The term “edge cutting” as used herein means a state where theultrasonic sensors next to each other or the pressure sensors next toeach other are independent. A state where the supporting body is notcompletely separated but a separating groove is partially formed is alsoreferred to as “edge cutting”.

Since the pressure sensor and the ultrasonic sensor are each supportedby the sensor substrate and mechanically divided while including thesupporting body, they do not interfere with each other, making itpossible to detect pressure with high accuracy.

In the sensor array 4C, the sensors 5C and 6C may be alternatelyprovided at equal distances along, for example, a predetermined firstdirection (X-direction) and a second direction (Y-direction)perpendicular to the first direction (X-direction).

Also in this case, a structure in which a protective film 55C is removedmay be used. Then, since the height from the sensor substrate 45C to atop of the pressure sensor 6C is higher than the height from the sensorsubstrate 45C to a top of the ultrasonic sensor 5C, the top of theultrasonic sensor 5C does not contact an object. Therefore, theultrasonic sensor 5C can escape deterioration due to pressure andmaintain high reliability (resistance to pressure).

Configuration of Ultrasonic Sensor

FIG. 25 is the cross-sectional view showing the configuration of thesensor array 4C including the ultrasonic sensor 5C.

The ultrasonic sensor 5 includes a second supporting film, a secondpiezoelectric body 53C, the second frame body 54C, and the protectivefilm 55C which are stacked in order on the second supporting body 51C.

The second supporting film and the second piezoelectric body 53Cconstitute an ultrasonic transducer portion.

The second supporting body 51C is formed of a single-crystal siliconsubstrate and formed to a thickness of about 200 μm. In the secondsupporting body 51C, a circular second opening 51D, in plan view whenthe second supporting film is viewed from the film thickness direction,is formed by dry etching.

The second supporting film closes the second opening 51D of the secondsupporting body 51C and is configured of a first oxide film 52C and asecond oxide film 52D which are stacked on the surface of the secondsupporting body 51C. The first oxide film 52C is formed of, for example,SiO₂ and formed to a thickness of about 1 μm by thermally oxidizing thesurface of the single-crystal silicon substrate of the second supportingbody 51C. The second oxide film 52D is formed of, for example, ZrO₂ andformed on the first oxide film 52C so as to have a thickness of about 3μm by depositing Zr by sputtering and thermally oxidizing the same.

The diameter dimension of the second opening 51D is appropriately set ina range from, for example, about one hundred μm to several hundreds μmaccording to the natural frequency of a second diaphragm portion. Thesecond diaphragm portion vibrates, whereby ultrasonic waves aretransmitted toward the object 10 (refer to FIG. 1) side.

The second piezoelectric body 53C is a film-like member which is formedconcentrically with the second opening 51D in plan view of the sensor.The diameter dimension of the second piezoelectric body 53C is smallerthan the diameter dimension D′ of the second opening 51D. The secondpiezoelectric body 53C includes a second piezoelectric film 531C andelectrodes (a lower electrode 532C and an upper electrode 533C) whichapply voltage to the second piezoelectric film 531C. The term “diameterdimension of piezoelectric body” as used herein means the diameter of aregion where the lower electrode, the piezoelectric film, and the upperelectrode are stacked.

The second piezoelectric film 531C is formed of, for example, leadzirconate titanate (PZT) made into a film. The lower electrode 532C isformed below the second piezoelectric film 531C. The upper electrode533C is formed on the second piezoelectric film 531C.

The upper electrode 533C and the lower electrode 532C are drawn througha not-shown drawing portion which is formed on the back side (the secondopening 51D side) of the ultrasonic sensor 5C, are connected to anot-shown control portion of the sensor array 4C, and apply apredetermined voltage to the piezoelectric film 531C based on a voltagesignal input from the control portion.

The second frame body 54C is cylindrically formed of a permanent resistmade of a synthetic resin material having flexibility and formed to athickness of about 100 μm to 600 μm. Moreover, with a cylindrical innerperipheral wall provided in the second frame body 54C, a cavity alongthe film thickness direction of the second supporting film is formed.The second frame body 54C is formed such that in plan view when viewedfrom the film thickness direction of the second supporting film, acylindrical inner peripheral edge of the cavity which is cylindrical ispositioned to be overlapped with an inner peripheral edge of the secondopening 51D or positioned outside of the inner peripheral edge. In thiscase, the inner diameter dimension of the second frame body 54C isformed so as to have substantially the same dimension as that of thesecond opening 51D (the case of overlapping). In the cavity of thesecond frame body 54C, a membrane is contained. For example, the secondframe body 54C can be formed using permanent resist TMMR™ S2000 of TOKYOOHKA KOGYO CO., LTD.

The protective film 55C is a portion which contacts the object 10, isformed of a dry film resist made of a synthetic resin material havingflexibility, similarly to the second frame body 54C, and is formed to athickness of about 100 μm. Moreover, the protective film 55 is formed ina ring shape to cover an upper end surface of the second frame body 54C.For example, the protective film 55 can be formed using dry film resistTMMF™ S2000 of TOKYO OHKA KOGYO CO., LTD.

Configuration of Pressure Sensor

FIG. 25 is the cross-sectional view showing the configuration of thesensor array 4C including the pressure sensor 6C.

The pressure sensor 6C detects pressure when, for example, the graspingsurfaces 31 of the arms 3 of the grasping apparatus 1 (refer to FIG. 1)grasp the object 10. The pressure sensor 6C includes a supporting film,a piezoelectric body 63C (a piezoelectric film 631C, a lower electrode632C, and an upper electrode 633C), the frame body 64C, and a sealingfilm 65C which are stacked in order on the supporting body 61C.

The supporting film closes an opening 61D of the supporting body 61C andis configured of a first oxide film 62C and a second oxide film 62Dwhich are stacked on the surface of the supporting body 61C. Thesupporting film and the piezoelectric body 63C constitute a pressuredetecting portion 9C.

The frame body 64C is formed cylindrically, similarly to the secondframe body 54C of the ultrasonic sensor 5C, and has a cavity. In thecavity, a membrane including a diaphragm portion which is a portion ofthe supporting film where the opening 61A is closed and thepiezoelectric body 63C which is provided on the diaphragm portion iscontained.

Thus, a silicone oil 20C as a pressure medium is filled in the innerspace 66C formed of a cylindrical inner peripheral wall of the cavity,the sealing film 65C, and the pressure detecting portion.

The sealing film 65C closes the inner space 66C to seal the silicone oil20C. As the material to be filled in the inner space 66C, any materialwhich disperses pressure may be used. Other than the silicone oil 20C,for example, a silicone rubber, a polymer gel, a synthetic gel, anatural gel, a polymer resin, or the like may be used. The frame body64C is formed such that in plan view when viewed from the film thicknessdirection of the supporting film, a cylindrical inner peripheral edge ofthe cavity which is cylindrical is positioned to be overlapped with aninner peripheral edge of the opening 61D or positioned outside of theinner peripheral edge. In this case, the inner diameter dimension of theframe body 64C is formed so as to have substantially the same dimensionas the diameter dimension D of the opening 61D (in the case ofoverlapping).

The sealing film 65C is a portion which contacts the object 10 (refer toFIG. 1), similarly to the protective film 55C, and is formed in acircular shape so as to close the inner space 66C to seal the siliconeoil 20C. Moreover, the sealing film 65C is a portion which seals thesilicone oil 20C and contacts the object 10. The sealing film 65C isformed of the same material as that of the protective film 55C. Forexample, the sealing film 65C can be formed using dry film resist TMMF™S2000 of TOKYO OHKA KOGYO CO., LTD.

Since the silicone oil 20C is filled in the inner space 66C, an impactwhen the object 10 contacts the sealing film 65C is dispersed over theentire membrane 8.

When a pressure medium filled in the inner space 66C is a material whichdoes not leak, such as a polymer gel, the sealing film 65C may not beprovided.

Method for Manufacturing Sensor Array

Next, a method for manufacturing a sensor array using a step of formingthe groove LB, in which the sensor substrate 45C is bonded to the lowersurface side of the common supporting body 51C, 61C and thereafter, edgecutting is performed for the common supporting body 51C, 61C whileleaving at least a portion of the sensor substrate 45C, will bedescribed. FIGS. 26 to 27C are step cross-sectional views showingmanufacturing steps of the sensor array. In FIGS. 26 to 27C,manufacturing steps of the ultrasonic sensor 5C are shown on the leftwhile manufacturing steps of the pressure sensor 6C are shown on theright.

In the following description, a pair of ultrasonic sensor 5C andpressure sensor 6C are described. However, this is applicable also tothe case where a plurality of ultrasonic sensors 5C and pressure sensors6C are provided (refer to FIG. 2).

As for the way of dividing, the pressure sensors 6C or the ultrasonicsensors 5C may be once divided into individual ones, and thereafter,they may be bonded to the sensor substrate 45C on another occasion.Moreover, some of the pressure sensors 6C or the ultrasonic sensors 5Cmay be collectively divided.

The description for steps of preparing a single-crystal siliconsubstrate which serves as the common supporting body 51C, 61C; forming,on one surface thereof, the common supporting film (formed of the firstoxide film 52C, 62C and the second oxide film 52D, 62D), thepiezoelectric body 63C, the second piezoelectric body 53C, the framebody 64C, and the second frame body 54C; filling a silicone oil in thecavity of the frame body 64C serving as the pressure sensor 6C; andcoating a dry film resist corresponding to the protective film 55C andthe sealing film 65C using a roll coating apparatus is similar to thatof the method for manufacturing the sensor array of the first embodimentdescribed above. Therefore, the description is omitted. FIG. 26 showsthe cross-sectional view in a state where the step of coating theprotective film 55C and the sealing film 65C is completed. Thesupporting film and the piezoelectric body 63C constitute the pressuredetecting portion 9C.

An example of forming the groove LB, in which the sensor substrate 45Cafter this step is bonded to the lower surface side of the commonsupporting body 51C, 61C and thereafter, edge cutting is performed forthe second supporting body 51C and the supporting body 61C while leavingat least a portion of the sensor substrate 45C, will be described below.

First, through-holes 40C are formed through the common supporting body51C, 61C using dry etching, and thereafter, an insulating layer isformed on the side wall of the through-hole 40C by CVD or the like.Next, Au is embedded in the through-hole 40C by plating, whereby thethrough-electrode 41C is formed. Next, the coated dry film resistcorresponding to the protective film 55C and the sealing film 65C isexposed and developed by a photolithography method. Further by anetching process, the protective film 55C and the sealing film 65C arepatterned into a desired shape. Thereafter, the lower surface side ofthe common supporting body 51C, 61C is dry etched to form the secondopening 51D and the opening 61D having substantially the same diametersas the inner diameter dimensions of the second frame body 54C and theframe body 64C. FIG. 27A shows the cross-sectional view in a state wherethe steps so far are completed.

Next, edge cutting is performed to divide the ultrasonic sensor 5C andthe pressure sensor 6C. FIG. 27B shows the cross-sectional view in astate where the steps so far are completed.

Next, the ultrasonic sensors 5C and the pressure sensors 6C are arrangedand fixed on the sensor substrate 45C with a gap having the width of thegroove LB, whereby the sensor array 4C including the plurality ofultrasonic sensors 5C and pressure sensors 6C on the sensor substrate45C is formed. FIG. 27C shows the cross-sectional view in a state wherethe steps so far are completed.

Although, in the embodiment, an example of including the ultrasonicsensors 5C and the pressure sensors 6C has been described, a sensorarray only including the pressure sensors 6C can be formed similarly.

In the sensor array of the embodiment, the following advantageouseffects can be provided in addition to the advantageous effects in thefirst to third embodiments.

Since the ultrasonic sensor 5C and the pressure sensor 6C are arrangedvia the groove therebetween (independently), it is possible to suppressthe transmission of vibrations of the membrane of the ultrasonic sensorto the pressure sensor. That is, since the influence of vibrations fromthe ultrasonic sensor on the piezoelectric body or diaphragm portion ofthe membrane of the pressure sensor is reduced, the pressure sensor candetect pressure with good accuracy.

Since the ultrasonic sensor 5C and the pressure sensor 6C are oncedivided and then bonded to the sensor substrate 45C, the embodiment canalso deal with the sensor substrate 45C larger than the secondsupporting body 51C or the supporting body 61C. Moreover, since thesecond supporting body 51C or the supporting body 61C is usually moreexpensive than the sensor substrate 45C, the manufacturing cost can bereduced by once dividing the ultrasonic sensor and the pressure sensorand then bonding them to the sensor substrate 45C.

Modifications of Embodiments

The invention is not limited to the embodiments described above, butvarious kinds of changes or improvements can be added to the embodimentsdescribed above. Modified examples will be described below.

First Modified Example

A description will be made with reference to FIG. 8. FIG. 8 shows amodified example according to the invention.

In the embodiment, the inner diameter dimension of the frame body 64 hassubstantially the same dimension as the diameter dimension D of theopening 61A. However, the modified example differs from the embodimentin that the inner diameter dimension of the frame body 64 is larger thanthe diameter dimension D of the opening 61A.

Second Modified Example

A description will be made with reference to FIG. 2. In FIG. 2, thepressure sensors 6 and the ultrasonic sensors 5 are arranged at equaldistances from each other on the common supporting body 51, 61 in theembodiment. However, they are not limited to this arrangement, but anyarrangement may be adopted. Specifically, as long as the pressuresensors 6 and the ultrasonic sensors 5 are uniformly arrangeddispersedly in the plane of the common supporting body 51, 61, avariation does not occur between a position at which the ultrasonicsensor 5 recognizes an object and a position at which the pressuresensor 6 detects a force grasping the object.

Third Modified Example

A description will be made with reference to FIGS. 3A and 3B. In FIG.3A, the ultrasonic sensor 5 is configured to transmit ultrasonic wavestoward the membrane 8 side. However, the ultrasonic sensor 5 may beconfigured to transmit ultrasonic waves also toward the second opening51A side.

Fourth Modified Example

A description will be made with reference to FIG. 7B. In FIG. 7B, theframe body 64 and the second frame body 54 of the ultrasonic sensor 5and the pressure sensor 6 are formed independently of each other.However, the second frame body 54 and the frame body 64 next to eachother may be integrated, so that the pressure sensor 6 and theultrasonic sensor 5 may be configured so as to be paired.

Fifth Modified Example

A description will be made with reference to FIGS. 9 and 10A. As shownin FIGS. 9 and 10A, an example in which the pressure sensors 106 each ofwhich has the frame body 164 whose outer shape is a square are arrangedvia the groove G on the supporting body 161 included in the sensor array180 has been described. However, the outer shape is not limited to arectangle. For example, a shape, such as an isosceles triangle, a righttriangle, a trapezoid, or a regular hexagon, which fills a plane may bearranged at distances corresponding to the groove G. In the case ofusing the outer shape described above, when excessive pressure isapplied to the pressure sensor 106, the pressure sensor is pushed to thenext frame body 164 at a plane. Therefore, compared to the case where,for example, the outer shape of the frame body 164 is a circle or thelike, resistance to high pressure can be further improved.

Moreover, as shown in FIG. 13, when the example is applied to the sensorarray 281 having also the ultrasonic sensors 205, some of the pressuresensors 206 may be replaced with the ultrasonic sensors 205. Also inthis case, a similar advantageous effect can be obtained.

Sixth Modified Example

A description will be made with reference to FIGS. 10A and 14A. As shownin FIGS. 10A and 14A, as the description for the sensor arrays 180 and281, the sensor arrays in which the planar shape of diaphragm portions107 and 207 and the second diaphragm portion 207B is a circle have beendescribed. However, the planar shape may be an ellipse, a rectangle, aregular hexagon, or any other shape. By making the outer shapeellipsoidal or rectangular for example, it is possible to improve theeffective areas of the diaphragm portions 107 and 207 and the seconddiaphragm portion 207B in the frame body 64 and the second frame body54. Moreover, by making the outer shape regular hexagonal, andaccordingly, by making the outer shape of the frame body 64 and thesecond frame body 54 regular hexagonal, the effective areas of thediaphragm portions 107 and 207 and the second diaphragm portion 207B canbe highly secured.

Seventh Modified Example

A description will be made with reference to FIG. 14A. In the case ofthe sensor array 281 including the ultrasonic sensors 205 in addition tothe pressure sensors 206 shown in FIG. 14A, the outer shape of the framebody 264 (254) may be a circle or any other shape without limiting tothe shape which fills a plane. As long as the pressure sensor 206 andthe ultrasonic sensor 205 are arranged to be spaced from each other bythe groove K, when the pressure sensor 206 is deformed within theelastic limit thereof, the frame body contacts the second frame body 254of the ultrasonic sensor 205, and a signal from the ultrasonic sensor205 is modulated by this contact. Therefore, this modulated amount isdetected, and pressure is adjusted, whereby the reliability of thepressure sensor 206 can be improved.

Eighth Modified Example

A description will be made with reference to FIGS. 10A to 10C, 13, 14A,14B, and 18 to 21B.

FIG. 18 is a perspective view of a sensor array. FIG. 19A is a plan viewof the sensor array; FIG. 19B is a cross-sectional view taken along lineA-A′ of the plan view shown in FIG. 19A; and FIG. 19C is a schematiccross-sectional view when the sensor array is subjected to pressure fromthe object 10. FIG. 20 is a perspective view of a sensor array. FIG. 21Ais a plan view of the sensor array shown in FIG. 20; and FIG. 21B is across-sectional view taken along line A-A′ of the plan view shown inFIG. 21A.

A sensor array 300 shown in FIG. 18 includes a plurality of pressuresensors 306 mounted on a supporting body 361. In the sensor array 180shown in FIGS. 10A to 10C, the sealing film 165 is provided only for thepressure sensor 106, but, as shown in FIG. 18, this may have aconfiguration including a sealing film 365 over the entire surface ofthe sensor array so that the sealing film is common to frame bodies 364.In this case, pressure applied to the pressure sensor 306 is dispersedby the sealing film 365 as shown in FIGS. 19B and 19C because the sensorarray has a structure shown in FIGS. 18 and 19A. Therefore, the sensorarray 300 which is less susceptible to breakage can be provided.

In the case of the sensor array 481 including ultrasonic sensors 405 inaddition to pressure sensors 406, the sensor array may have aconfiguration including, instead of the sealing film 265 shown in FIGS.13, 14A, and 14B, a sealing film 465 excepting a region of theultrasonic sensors 405 as shown in FIG. 20. The sensor array 481 shownin FIG. 20 includes the plurality of ultrasonic sensors 405 in additionto the plurality of pressure sensors 406 mounted on a common supportingbody 451, 461. As shown in FIGS. 21A and 21B, the sealing film 465 isprovided on a frame body 464 but the sealing film 465 is not provided ona second frame body 454. In this case, pressure applied to the pressuresensor 406 is dispersed by the sealing film 465 because the sensor arrayhas the structure shown in FIGS. 20, 21A, and 21B. Therefore, the sensorarray 481 which is less susceptible to breakage can be provided.

Ninth Modified Example

A description will be made with reference to FIG. 2.

In the first embodiment, an example in which the pressure sensors 6 andthe ultrasonic sensors 5 are integrated on one substrate has beendescribed. This may be separated by, for example, dicing and then bondedto another substrate for use. In this case, especially when the pressuresensors 6 or the ultrasonic sensors 5 are formed in a wide range, thecost can be reduced because a large substrate is not required.

Tenth Modified Example

A description will be made with reference to FIGS. 14A, 14B, and 28.

In the third embodiment as shown in FIG. 14B, electrical conduction isestablished between the ultrasonic sensor 205 and the pressure sensor206, and the not-shown control portion which controls the ultrasonicsensor 205 and the pressure sensor 206 via the electrode pattern(wiring) formed on the second supporting film 252 and the supportingfilm 262 (in a direction from the common supporting body 251, 261 towardthe frame body 264 and the second frame body 254). That is, the wiringis formed on the upper side of the sensor array 281, and the ultrasonicsensor 205 and the pressure sensor 206 are electrically conducted to thecontrol portion via the wiring. In this case, since the wiring locatedat the region overlapping with the groove K for edge cutting is removed,the wiring is formed so as to avoid the portion of the groove K. In themodified example, on the other hand, wirings 44A and 44B forelectrically conducting to the through-electrodes 41C are formed bysputtering Au and then patterning the same as shown in FIG. 28. Thewirings 44A and 44B are provided. Therefore, in plan view of the commonsupporting body 251, 261, the wirings 44A and 44B can be formed also inthe portion of the groove K for edge cutting. That is, the wiring regioncan be formed also in the region of the groove K for edge cutting, whichcan improve the degree of freedom of the wiring pattern.

The entire disclosure of Japanese Patent Application Nos. 2011-069518,filed Mar. 28, 2011 and 2011-104095, filed May 9, 2011 are expresslyincorporated by reference herein.

1. A pressure sensor comprising: a supporting body which has an opening;a pressure detecting portion which includes a supporting film providedon the supporting body and having a diaphragm portion closing theopening, and a piezoelectric body provided on the diaphragm portion anddeflecting to output an electric signal; a frame body which has, on thepressure detecting portion, a cylindrical cavity along a film thicknessdirection of the supporting film, and is formed, in plan view whenviewed from the film thickness direction of the supporting film, at aposition where a cylindrical inner peripheral wall of the cavityoverlaps with an inner peripheral edge of the opening, or outside of theinner peripheral edge of the opening; a sealing film which closes theframe body; and a pressure medium which is filled in an inner spaceformed of the cylindrical inner peripheral wall of the cavity, thesealing film, and the pressure detecting portion.
 2. The pressure sensoraccording to claim 1, wherein the frame body has flexibility
 3. A sensorarray comprising a plurality of the pressure sensors according to claim1 arranged therein, wherein a gap is formed between frame bodies of thepressure sensors next to each other.
 4. A sensor array comprising: apressure sensor which has a supporting body which has an opening, apressure detecting portion which includes a supporting film provided onthe supporting body and having a diaphragm portion closing the opening,and a piezoelectric body provided on the diaphragm portion anddeflecting to output an electric signal, a frame body which has, on thepressure detecting portion, a cylindrical cavity along a film thicknessdirection of the supporting film, and is formed, in plan view whenviewed from the film thickness direction of the supporting film, at aposition where a cylindrical inner peripheral wall of the cavityoverlaps with an inner peripheral edge of the opening, or outside of theinner peripheral edge of the opening, a sealing film which closes theframe body, and a pressure medium which is filled in an inner spaceformed of the cylindrical inner peripheral wall of the cavity, thesealing film, and the pressure detecting portion; and an ultrasonicsensor which has a second supporting body having a second opening, andan ultrasonic transducer portion including a second supporting filmwhich is provided on the second supporting body and has a seconddiaphragm portion closing the second opening, and a second piezoelectricbody which is provided on the second diaphragm portion and deflects bythe application of voltage.
 5. The sensor array according to claim 4,wherein the ultrasonic sensor further includes a second frame body whichhas, on the ultrasonic transducer portion, a cylindrical second cavityalong a film thickness direction of the second supporting film, and isformed, in plan view when viewed from the film thickness direction ofthe second supporting film, at a position where a cylindrical innerperipheral wall of the second cavity overlaps with an inner peripheraledge of the second opening, or outside of the inner peripheral edge ofthe second opening.
 6. The sensor array according to claim 5, whereinthe sensor array includes a plurality of the pressure sensors and aplurality of the ultrasonic sensors, and a gap is formed between framebodies of the pressure sensors next to each other, between second framebodies of the ultrasonic sensors next to each other, or between a framebody of the pressure sensor and a second frame body of the ultrasonicsensor next to each other.
 7. The sensor array according to claim 6,wherein the supporting body and the second supporting body are a commonsupporting body which is common to them, and a height from the commonsupporting body to a top of the pressure sensor is higher than a heightfrom the common supporting body to a top of the ultrasonic sensor. 8.The sensor array according to claim 6, wherein the pressure sensors andthe ultrasonic sensors have a two-dimensional array structure in whichthe pressure sensor and the ultrasonic sensor are alternately arranged.9. The sensor array according to claim 3, wherein a dimension of the gapis set such that when a first pressure is applied to the pressuresensor, the frame body deforms to contact the frame body of the nextpressure sensor, and the first pressure is smaller than an allowablepressure of the pressure sensor.
 10. The sensor array according to claim6, wherein a dimension of the gap is set such that when a first pressureis applied to the pressure sensor, the frame body deforms to contact theframe body of the next pressure sensor or contact the second frame bodyof the next ultrasonic sensor, and the first pressure is smaller than anallowable pressure of the pressure sensor.
 11. A method formanufacturing a sensor array including a plurality of pressure sensors,comprising: forming a supporting film on a supporting body and forming apiezoelectric body on the supporting film to thereby form a plurality ofpressure detecting portions; forming, on the plurality of pressuredetecting portions, a frame body layer which covers the piezoelectricbody; removing portions of the frame body layer formed in the forming ofthe frame body layer to thereby form frame bodies each of which includesa cavity having a cylindrical inner peripheral wall so as to have a gapbetween frame bodies next to each other; filling a pressure medium inthe cavity; and forming, by a roll coating method, a sealing film whichcloses the cavity to seal the pressure medium.
 12. The method formanufacturing the sensor array according to claim 11, further comprisingforming a groove which divides the supporting film at a positionoverlapping with the gap in plan view when the supporting film is viewedfrom a film thickness direction thereof.
 13. The method formanufacturing the sensor array according to claim 11, furthercomprising: bonding a sensor substrate to the lower side of thesupporting body; and forming, while leaving at least a portion of thesensor substrate, a groove which divides the supporting body at aposition overlapping with the gap in plan view when the supporting filmis viewed from a film thickness direction thereof.
 14. The method formanufacturing the sensor array according to claim 11, furthercomprising: dividing, after the forming of the sealing film, the sensorarray into blocks each of which includes one or more the pressuresensors; and bonding the block to a sensor substrate such that the lowerside of the pressure sensor is positioned on the sensor substrate side.15. A method for manufacturing a sensor array including a plurality ofpressure sensors and a plurality of ultrasonic sensors, comprising:forming a supporting film on a supporting body and forming apiezoelectric body on the supporting film to thereby form a plurality ofpressure detecting portions and a plurality of ultrasonic transducerportions; forming, on the plurality of pressure detecting portions andthe plurality of ultrasonic transducer portions, a frame body layerwhich covers the piezoelectric body; removing portions of the frame bodylayer formed in the forming of the frame body layer to thereby form aplurality of frame bodies which are defined by a gap and each of whichincludes a cavity having a cylindrical inner peripheral wall; filling apressure medium in some of the cavities; and forming, by a roll coatingmethod, a sealing film which closes the cavity to seal the pressuremedium.
 16. The method for manufacturing the sensor array according toclaim 15, further comprising forming a groove which divides thesupporting film at a position overlapping with the gap in plan view whenthe supporting film is viewed from a film thickness direction thereof.17. The method for manufacturing the sensor array according to claim 15,further comprising: bonding a sensor substrate to the lower side of thesupporting body; and forming, while leaving at least a portion of thesensor substrate, a groove which divides the supporting body at aposition overlapping with the gap in plan view when the supporting filmis viewed from a film thickness direction thereof.
 18. The method formanufacturing the sensor array according to claim 15, furthercomprising: dividing, after the forming of the sealing film, the sensorarray into blocks each of which includes one or more the pressuresensors or the ultrasonic sensors; and bonding the block to a sensorsubstrate such that the lower side of the pressure sensor is positionedon the sensor substrate side.
 19. A grasping apparatus including thesensor array according to claim 3 and grasping an object, comprising: apair of grasping arms which grasp the object and each of which isprovided with at least one the sensor array on a contact surface withwhich the object contacts; a grasp detecting unit which detects agrasping state of the object based on an electric signal output from thesensor array; and a drive control unit which controls the driving of thegrasping arms based on the grasping state.
 20. A grasping apparatusincluding the sensor array according to claim 4 and grasping an object,comprising: a pair of grasping arms which grasp the object and each ofwhich is provided with at least one the sensor array on a contactsurface with which the object contacts; a grasp detecting unit whichdetects a grasping state of the object based on an electric signaloutput from the sensor array; and a drive control unit which controlsthe driving of the grasping arms based on the grasping state.